I'm a new guy at this board and I'm an analytical so sorry if I try too hard to get the reasoning behind all the pertinent technical stuff explained. I'm in Calgary AB Canada. I didn't buy this car as a lark.

Up front: Grad 77 N.A.I.T. I'm an Engineering Technologist by schooling, engine machinist (14 years) by trade and have been is sales for 30 years with places like Cummins and Mack. I had 2 cars at 17, one a 66' Canso 283 4spd 4.10 gears (other a 63 Chev Wagon;-) . I've also built dozens of street strip and competition engines and assembled hundreds of other engines over the last 40 years or so.

This is my 1st, 3rd gen Camaro. In 2003 and until 2017 had an 11.5 second (4000ft air density) street strip 3400lb, 2nd Gen 74 Camaro which saw over 350 trouble free passes in 6 years until they closed our track in 2011. Now I want a "detuned" version of the same concept. I like to prove that you don't need to spend gobs of money to go fast and be reliable.

That 11.5/115 mph true street car Camaro was a 406 SBC, carbed, no nitrous, no turbo, 4 seat hardtop that I spent grand total of $17,000 Cdn on including the car. NHRA/IHRA rules at the time and maybe still are convertibles /T-Tops must have a 6 point if quicker than 13.5. Hardtops can go 11.5. My goal then was the same as now except then I wanted to push that 11.5 thing to the limit. Then, the only guys quicker than me all had roll cages. And lots of guys with cages couldn't touch me! Good fun!

I explained all that to show you the requirements and conclusions for my next project.

1. Street/strip that can drive at 2200 rpms in OD, on the highway and still nail over 100 mph in a 1/4.

2. hardtop, lightweight and slippery.

3. Easy and cheap to hot rod. SBC 2000-6000 broad torque curve.

4. I hate body work. Solid steel or nothing. Do not care about the paint unless it's the clear coat.

Happy Conclusion: Acquired a 1985 Z-28 Camaro Hardtop, V-8 carbed, auto O.D. Solid steel ;-)

The car fits all the above and because it was a 305 9.5:1 Rochester version I will NOT being going back and forth to "Pick a Part" to swap in a larger small block. I always look at the car as a whole unit. The car has to be able to easily handle the area under the torque curve and how much shock that power is applied with. And it has to be able to stop, before it can go! I will spend the money to strengthen the 7.5 axle. (already well into acquiring those parts). 700R4 allows for less shock and should be reliable. Whatever displacement I go for I can tune the carb to launch off idle 800ish and like to do it that way. With a 2800 stall it'll flash right up there. My 74 came off idle and still posted 1.58 60fts.

We all loved the early true Z-28s that gave the logo its legend. This car has Z-28 decals. I plan to make it a "real" Z-28. I do want a sleeper and to retain the stock hood and I do know I'll have cold air challenges.

I'm just getting going and bought the car in April. I will post again right away with pics and where I am now. It does run but isn't yet registered. I hope to have the upgrades inc. engine by next spring but who knows. Paint and interior are at least 2 years away?

Too analytical?

"Horsepower sells cars, torque wins races"

 

Heres the car:

The AD said $3000 and "includes extra parts" and that was it.
It was a treasure trove.

The "extra parts"
A complete new interior still in the boxes and the stock interior isn't bad!
brand new control arms and panhard bar with Poly
The 305 was just overhauled and it was nice job AND has new Hedman Hedders
All new weather stripping still in the box
A complete new stock exhaust system end to end
800 page service manual AND 800 page parts manual

And he threw int he solid steel Camaro! Everything works.





Seller was my age but just ad major surgery on his right hand and said that was it he was done. If he'd listed those parts in detail he'd have got way more. I think I scored well.

 

i dunno about analytical, conflicted maybe, or uninformed (don't read that as an insult). you want mid 11's, a 'dependable' street car, you know that torque wins races, but you get a 3500lb car that has an incapable rear end, a 305 (2000-6000????), and you 'will NOT ... swap in a larger small block. ? you gotta change yer strategy or prepare to spend a WAD.

welcome, this could be interesting, lotsa people on this site watching..... ( ~ 50,000 members - claimed )

 

Thanks for the reply: Read carefully: 100 mph goal. I did NOT say I wanted 11 seconds again. I demonstrated I've done this before.and I KNOW what 11 seconds takes. Please note."detuned version". "larger cubic inch displacement"
Sorry if reading comprehension isn't your strong suit ( no insult intended ) ;-)

 

KIJIJI in Canada is great. Don't know if its the states. I'm sure KIJIJI or the equivalent is there. Chevy in great shape is abundant.

As our esteemed colleague notes a 7.5 is a pretty flimsy axle. I'm certain for a 350 hp 400 ft lb small block it can be manageable. There's a great post on 7.5s in Tech right here!

I have the Poly control arms and panhard bar with the car. I'll get the torque arm poly piece.
I planned from the out set to go Eaton posi 28 spline, GM or Richmond gears at xxx ratio and Moser 28 spline axles.
Weld the tubes into the pumpkin (three short welds) and a gridle and a solid bearng spacer.

2 days ago I scored this from some old racing pals for $280 bucks. Its from an 88 S-10 and the Eaton is 28 spline.
Excellent shape GM 4.10s came with it so why not? other than smaller tooth area? I will not be shocking it and will have overdrive.
I think I'm on the right track with securing the flyweight rear axle.

BTW there is no air conditioning and the listed weight is 3200 or so overall.

 

camertom, would you like me to move this thread to the "members Camaros" section? That's where most people land their build threads.

https://www.thirdgen.org/forums/members-camaros/

 

Sure that's fine. A couple of the Canadian guys suggested this section. By all means.

Thanks

 

The 7.5 GM 10 bolt is a horrible performance rear end. There is no debating it. You can search for videos on YouTube of stock-stockish fourthgen Fbodys breaking the rearends. The problem also becomes logarithmically worse as your rear end gear ratio becomes numerically larger. The 4.10 gears are very weak--you can also search for comparative pictures of the gear ratios of the 10 bolt that demonstrate this. The ten bolt is usually adequate for thirdgens that will not use sticky tires and will not be making over 300 hp and will just be cruising around town. That's it. If it is a money issue than throw a stout rear end cover with the girdle caps on and take it easy until you can get a performance rear end.

 

Well thanks for your concerns. And you can search these sites for hundreds of guys who run waaaaay more power through them, successfully, than I'm considering. Of course there.s no videos of them NOT blowing up.

Is that 300 hp rear wheel or flywheel? Is that 300 hp with what accessories? Is that with automatic or standard? Is that with a trans brake and a 3000 rpm launch? Perhaps you could ask the administrators to flag the "beefing up the 7.625 10 bolt" in the Tech help section?
FWIW a 175hp 305 with a standard transmission can be wound up to 5000, dumped and blow up the stock rear end. A blanket "300 hp" statement is kinda of low info.

No question the 4.10s have too many teeth LOL. However I can and will tune the 350s Roch to come of the line off idle about 800 900.
I'm building it up for broad range, low end torque band 2000-5000 rpms or so. 1 hp/cube. carbed is not that difficult to build too. 380-400 ft lbs....flywheel and including. Peak HP around 5500.

You can't beat an Eaton Posi and it is a 28 spline. I may or may not run the 4.10s (they were FREE and came with the Eaton.) and may go to 3.55s as the 700r4 has a really low 1st. I will get Moser axles, I will weld the tubes into the pumpkin, I will run a solid piece where the crush sleeve goes so the pinion doesn't walk and will run a girdle and already have poly bushed control arms and panhard bar.

13.0 and 100 mph is the goal however I will be at 3000 ft air density.

Still think it'll grenade?

 

Why yes I do. The problem is still the physical size of the gears. The 10 that came in our vehicles is not strong and nothing you do will address it's main weak point, the gear size. You're going to dump a time and money in a 10 bolt and by the time you're done you could be at least 1/2 way towards the cost of a real rear-end. But you sound like someone who has made up their mind on everything and nothing anybody says is going to change it so I'm not going to waste my time posting pictures and links and explanations. I hope you're able to enjoy the car without too many frustrations and money.

 

Thanks again and I'm not hell bent on anything I just think while your "right", your also wrong regards just how limiting it is. I'm running 350 flywheel hp. and still may back off the gears to 3.55. tho early math through the traps still likes the 4.10s.

I kind find just as much support as you can find detractors. Quick search just now...Super Chevy article used a strengthed 7.625" 10 bolt w/4.10 Richmond gears behind a hopped up LS6: " it can take up to about 400-450 with drag radials so if you're not making more than that don't bother with a new rear. ..... and don't dump your clutch at 5000 rpms with slicks." Co-incidence I already said that!
I'm fully aware of its limitations and heard similar stuff 20 years ago when I ran a carbed only 515 hp and a torque monster 520 plus ft lbs thru a 10 bolt 8.5. ( BTW off idle automatic 3000 stall) Same basic treatment on that axle and ran 11.56 and 1.58 60s on hot sticky drag radials in 3500 ft air density. That's about a 10.80-10.90 at sea level. It never even gave a second thought much less any problems after 6 years and 350 passes.

 

Welcome aboard camertom. Nice to see you with a build thread and good luck.

100 MPH in a 3650 lb chassis (this is what my coupe weighs with 200 lbs of driver and a half tank of fuel) can be done with 1HP/CI goal. If wouldn't take much to exceed that 305 HP either and still have the other qualities you're after. I bet you could tune the carbed 305 with the 700R4 and 3.54 gear to better than 25 MPG (CDN gallon) on the highway. My big cammed 350 has knocked 24 MPG steady state highway at 120 KPH between Edmonton and Calgary.

FWIW, regarding the rear end, the somewhat stronger 9-bolt these cars also came with got me into the 12's with a slight stall converter and McCreary Road Star treaded "slicks". The 3.70 pinion broke on that pass but had seen dozens of drag strip launches prior to that. 60' times started out at 2.0 when the car first dipped into the 13's at 100 MPH. Eventually getting to 1.78 60's, 12.96 @ 106 over three seasons of test and tune. Then it went bang. Swapped in a 3.27 gear in the same axle and went another couple of seasons getting the 60's down to 1.7 flat. There's not a lot of difference in strength between the 7.5" 10 bolt and 7.75" BW 9 bolt so your diff might go a long way.

 

I Thanks Skinny Z and I will be running a 350 not the 305. I will NOT run a 400-406 that'd be tempting fate with the 7.625. strengthened properly or not.

 

A 350? Well I can relate to that a little more. I'm in the first steps of an engine refresh or rebuild depending on what I find when I take the current lump part. Might even step up to 383 CID. That'll leave a really nice 3.48" rotating assembly for another build.
Do you have a 350 already? I saw you were gathering parts (heads and intake IIRC). Didn't see a shortblock. I'm guessing you have a favourite machine shop? I'll be looking around again myself.

 

Absolutely subscribe to larger cubic inch the better theory of engine building. All major FHP loses are pretty equal within any engine series including SBCs.. Piston diameter and stroke increase with some frictional losses. Its minor compared to the total FHP losses found in all SBCs or any engine series.

The crank bearings, seals, timing set, cam, springs and lifters, rockers, water pump, oil pump and distributor are all about equal losses in every SBC 265 to 400. Increasing cubes is almost like "free" power even with a modest ring increase loss. I considered a 383 or 400 but my goals are modest. I've settled on a good old fashion 350, 10.2:1 wedge head with intake ports for good low end air velocity. 165-170 cc is fine and those 492s are nicely, mildly ported and should be just fine. 275-290 to the rear wheels?

No don't have a short block yet. They are a "dime a dozen" on kijiji.LOL. $100-$300 take yer pick! I take my mic's, snap gauges as well as a straight edge and the Chevy Interchange Manual when I look at an engine block. I do look for casting shaft and have seen it in 70s and 80s blocks. I won't buy a complete engine used unless the heads are off it, cheap or not. I want to see bores and mains saddles. Already poked over 2 that were not acceptable.

I happen to like Muscle Motors just west of Strathmore. Haven't had a lot of work done in a while but when I did too many other shops in Calgary had a "we'll sell you our package" mentality. Muscle Motors Todd I think, got where I was going with my block 406 and why. They also have an oven cleaning set up that made that 80s vintage 400 block look like brand new.

 

New pics. This is what I've accomplished in the past month besides scoring a few parts deals.
Rattle can!!!

About 5-6 hours sanding at 220. Carefully washed and cleaned it then tack clothed. 7 coats each 1/2 hour apart. Not a run or mark in it. Its been nice and warm out so it should cure well. Hope to finish sand primer to 800 next week. On the other hand I hate body work so who knows if it even sticks!

 

Have you seen JB's machined block deal? They also have a SCAT rotating assembly as part of package deal. I'd been in touch with the SCAT rep for this area and we were working through changes in the bill of materials. Then COVID and everything kind of went sideways.


Nice work on the front end. I've a couple that need the same treatment.

 

Skinny................... 377 ci and you can use your current 3.48" stroke rotating assy. You just need a 400 block and new pistons. Match the piston weights and you're good to go.

 

Funny you should say that. That has been a part of the decision tree. I've been looking at the aftermarket 4.125" bore blocks and if this build reaches the most extreme application, that is open road event racing, the shorter stroke reduces the stresses on all of the rotating assembly. Something worth considering if I intend to be at or near WOT for many minutes at a time. I have to determine if my GM 5140 crank is up to the task first. I've encountered mixed opinions on that.

 

I have one of those cranks myself - the nitrided version. Before 4340 cranks became readily available, the 5140 GM cranks were the best for those of us that did not have unlimited $$$.

 

I'm a Scat fan. Great crankshafts. I have plenty of time.

 

I'm on the fence about SCAT. Not necessarily because of their quality, which I am finding positive reviews in that regard, but more about their origin. I'd really like to have a Made in the USA crankshaft for many reasons not the least of which is to say I support the North American manufacturing market. Which, not coincidentally, is where I made my living and continue to do so.

That said, I have explored SCAT's offerings in the stroker department. Their standard weight 4340 3.75" version seems reasonable enough. Their Pro Stock branded connecting rods are stroker clearanced and with the bolt upgrade they provide seem up to the task as well. The task being having the snot beat of them.

But for a build such as your own camertom, seeing as you're still on the hunt for parts, have you considered SCAT's 9000 series cast steel cranks? It was recommended to me by AMS Engines in Edmonton but their thinking was that I was just another street poser. Once I elaborated on my plans, the 9000 was removed from the discussion. On the other hand, I've also drag raced (no open road stuff then) Chevy's plain old cast crank. Seemed plenty happy with 6000 RPM shifts and the general abuse that comes with street driving. But modest levels of drag racing aren't all that hard on parts.

 

I ran the 74' with 510-520HP and with a broad torque curve through a Scat 9000 cast 3.750" crank. Nice generous radius's. Ran at least 14 years I know of.

ALL old 350 stock cranks need indexing. Back in the 80s at Moore's I took care of all 6 crankshaft grinders and the sub arc welding. The auto side had an index capable Berco I used many times, a really reliable set up with indexing heads. Zero on the first throw and I guarantee the last throw will be .005 -as much as .015 out. Thats why I like an aftermarket crank. They are indexed out of the crate.

Where is Scat made? I actually don't recall.

BTW Today I haven't a clue who is capable of index grinding.

 

Those SCAT 9000's appear remarkably tough. Certainly for drag racing. Not so sure about open road racing. I'm inclined to get a forging in that case.

My GM 5140 came out of old school race shop when I picked it up 20 odd years ago and then went through a couple of machining processes as well as balancing during the time I've had it. Old Henry ran the shop where I bought the crank. He was a Super Stock engine guy and it's a good bet that whatever could be done was done. That said, was it indexed? I can't say with certainty.

SCAT's forgings are made in China and the machining is done in the US. At least that was state of affairs in recent history.

I would think AMS Engines in Edmonton has the ability to index cranks given the kind of engines they build. It isn't on their list of services though.

 

Early Ford NASCAR cranks were all cast until 1968-70 or so until SVO came out.

I bet your old school guy knows about the value of indexing. How can you claim to have "balanced and blueprinted" it, an over used term if ever there was one. Many racers and even some veteran machinists I know don't actually understand it. An indexed crank is part of it. As is decking a block whether just make all 4 corners even or the full .025" for zero deck for quench. Pistons are almost always bang on and the rods have to be big end small end identical as well.

Just build all 8 cylinders identical down to the .0001 mark! Simple! And a joy to assemble when the degree wheels on it and pistons come perfectly to the top right on cue.

Does Scat call itself a "Product of USA" as opposed to "Made in USA"? That's a dead give away. Spicer automotive U Joints 20 years ago were simply the only product anyone would use. About 1996-2000 they were suddenly marked "Product of" instead of "Made in". Their.sales have been reduced especially in 4x4ing. In trucking they are somewhat popular still but mainly over the name.

Not familiar with AMS. I check out their website.

 

I worked at an automotive machine shop and the owner was also an SK Modified racer. You guys are right about the crankshafts and the indexing. George had a truckload of cranks brought to his shop because he wanted a perfect crank. He found only 1 in the entire truckload.

 

Update on parts gathering.

The power will be 350 cid 325-350HP 375-400 ftlbs naturally aspirated and through the 700R4

I have all my pieces for the rear axle together or on the way.

Eaton 28 spline posi and Moser 28 spline axles
Crush sleeve eliminator from Yukon and a Summit Girdle with pins to support the main caps on the diff
4.11s GM original
New control arms w/poly
New panhard bar w/poly
poly for the torque arm point on the diff

Some parts came with car, got a screaming hot deal on the \Eaton and Gears from kijiji and the Mosers and Girdle are new. As far as budget hot rodding goes I think I've done well with about $850.00 Cdn for everything and it should be as bullet proof a 7.5 as can be built.

I work for a Diesel truck shop and can get the tubes welded into the pumpkin easily and all the assembly. ( I've done about 2-3 crown and pinions in 40 years so I will defer to a few guys who've done waaaay more than me to set it up)

I have no idea what the max power I could run through it is however I'm very confident a street/strip 350/350 won't over power a set up like that. In fact I've mused about going 400 CID and still have plenty of time to think it over.

Also have a TD 7 qt, trap door oil pan to specifically fit 80-85 Camaro and windage tray coming.

 

Nice to see an update.
Parts gathering is one of my favourite parts of the hobby and something which I haven't gotten in to myself.
Did you find a 350 or have just concluded that this is what it will be? I saw mention of 400 CID too. Then there's always 383 cubes.
As for the 10-bolt, the only way you'll know is with a slick tired launch on a prepped track. It took about 400 lbs/ft, a loose converter and slicks to break the unprepped BW 9 bolt that I harvested out of an 86 Trans Am.

 

90% going with a simple 350. 2000-5800 rpm, very street able and should work well in O.D. automatic on the highway so I can go someplace like Nisku sometime in the future.The long term option is always there for an upgrade to a 400 short block. If you can't pull, build and install a small block chevy you're in the wrong hobby.

My version of the 350 involves static 10:1 or so comp ratio, a good .035-.040 or so quench and a cam selection based on dynamic compression 1st and LCA and lift 2nd. I also like to get rid of FHP and always run some kind of oil pan strategy and will go to electric fan as well. Lots of little savings and the heads I have now are fine for the correct flow and velocity for a moderate torque SBC. I could do better but at this point I think I should run 13.00 s and top 100 mph at 4000-5000 ft air density. That's all I want at this point is that 100 mph! High 12s at Nisku would be gravy.

I have a ratchet and a line lock so it will work properly on a drag strip.

 

That 350 recipe is not unlike a couple I've gone through.
The over-achiever in the lot was the 353: (4.020” x 3.48”),
10.05 SCR / 8.08 DCR,
5 cc Speed Pro hypereutectic piston,
stock rods w/ ARP bolts,
.030” deck (block undecked),
670 Holley,
RPM Air Gap,
Vortec heads. Decked .006”. 63 cc,
Comp XR276HR. 276/282, 224/230, 110 LSA, 106 ICL, 64 ABDC IVC,
Victor Reinz 5746 head gasket .026” x 4.120”,
Mid length headers, full 3" single exhaust,
Cranking pressure 185-190.
Daily driven. Good highway fuel economy. Went mid 12's @ 109 with the usual collection of other drag strip bits: Converter, 3.73 posi, drag bags, adjustable rear LCA mounts. Stock chassis otherwise.
The biggest deal, aside from traction (as the tires eventually went away over a few racing seasons), was the weight. At 3650 with a 200 lb driver, half a tank of fuel, glass hood, Spohn SFC's, iron heads, and a full interior, it certainly wasn't a lightweight.
Personal best with was a corrected 12.49@109. With a 3000 DA on that day, best time slip was 12.93@ 105. 60' was an abysmal 1.85. It had ripped off successive low 1.7's with better tires.
Since then I've stepped up with better heads, more cam and looser converter but something's coming undone in the engine (high RPM miss and some unusual tapping) so I haven't been to the track with the new combination. Might be a while too.

 

I like this combo, Skinny.

 

Thanks.
Like I said, it was an over-achiever. And dead nuts reliable. Probably made peak power around 5600-5700 but it pulled well past 6k. I'd use a little overspeed to get past the big 700R4 1-2 shift drop but other than that, shifted at 6000 mostly.

 

NICE.

 

Thanks Skinny nice to hear my parameters are in the ball park. Sorry to hear you may be diving back into the engine, good luck.

That cam BTW has the desired 45-47 intake closing ABDC when computed at .050. The 64 number sounds like the .003 ABDC IVC. When I do my my scratch planning math I get those kind of recommended cams.

1.8-1.7 60s aren't bad at all and at least you weren't 3 lengths behind out of the hole. So many kids on Friday nights back in the day were over 2.0 and just couldn't figure it out. Calgarys old track was 1000 ft higher than Nisku and 3000 ADs were unheard of but I do recall a few 3700-3800s.

 

Yep. Those numbers are all off the cam card and computed at .006".




As for 3000' DA, I'm more used to racing in Ontario. 600' track elevation. Had a few days where we were racing below sea level. I can't say I like racing here. A few times were +4000'.
1.71 was my best 60 and I'm pretty sure I have another tenth with the new spec engine/trans/converter. Broken though as it is it'll be a while before I find out.

 

Paint up date #1 all rattle can, mixed to match at body shop supply store. Then 2 part w/hardener rattle can clear coated and a month later its tough as nails and looks good for me to work on the power train now. Lots of careful cleaning and tac clothing between coats and stages.

Before and after and actually its all now attached and the lower fairings on it.

 

Update on my efforts to make my 1985 Z28 into something more like a 1970 Z-28.

Good score IMHO I've taken a look at 4-5 short blocks over the summer before buying this last week for $240.00 Cdn. The crank, rods and pistons were "thrown in".

I now have a great 355 engine foundation...and after examining the heck out of it, mocking it up, measuring every bore, the mains and rod big ends, I have a better deal than I hoped for. The seller really had little or no idea. He felt the crank was a write off ( it isn't!) and had no idea what the extension on the studs on the main caps were for. I explained windage to him.

Heres the 355 I will use in the Camaro



Typical 010 casting, 4 bolt block, clean, .bored 030 over and every bore is on the mark 4.030 -4.0305. Mains measure great and straight holds a .001" feeler strip on the saddles. Was very recently overhauled, run briefly??? and torn down due to excess end play.








Forged steel 1178 crank M.020 near max and rods .030 also near max. The Con Rod, side thrust clearances on all 4 throws are all good about .012-.014. The main bearing at the thrust end was worn away at least .020 on one side and yet there is no matching damage on the crankshaft main thrusts at all. Don't see it often, but I can't find anything else wrong on the crank in spite the main bearing thrust wear, And M .020-R .030 or not it's a nicely done crank.





Good rods and they measure great on big ends.

Forged TRW L2304 .030 pistons , low domed and make 10.7 to 11.4 to 1 depending on how I approach quench. The piston skirts are mint, almost untouched. I'm unsure of quality due to inclusions in piston tops. I'm also a bit antsy due to them measuring ,0075-.008 piston to wall. I know you can get away with it using forged pistons but I still prefer a tighter .004" 005".



I mocked up the crank in the block, it all spun well on the used bearings and used then one rod and piston, switching from throw to throw to physically check the piston to deck height on all 8 holes. I got all 8 bang on .025" below deck as hoped for! This block is straight,square and has never been decked simply punched out to 355. It also has 5 screw in studs with extensions for a windage tray. They MAY be a problem as they aren't original and change the torque distortion a bit.

All in all I have a great usable 355 .030 block, that just needs a good cleaning and I have a very good, quite possibly indexed forged steel crank ( there is no blue at all and no dings at all, no runout and yet its Rods .030) with all the radii in good shape and apparently the end play is from the bearing only, as the main thrust surfaces are still nicely ground on the crank..

It's a good foundation I hope and the forged crank gives it a real "Z-28" touch as they would have featured this set up even down to the 11 to 1 pistons in the 370HP 1970 engine. No matter what I have a block, crank and rods and lots of options for pistons.

 

A friend of mine, Doug, bought a '63 Chevy II Nova that had a 400 SBC in it with automatic transmission. One day, for whatever reason, he grabbed the lower pulley to rotate the crank, and we noticed that the crank moved back-and-forth in the block about 1/4". We figured that the worn out thrust bearing was from a stiff clutch sometime in the past. Long story short, we put a new crank and bearings in it, checking all clearances, everything was perfect. We got the engine back in the car and a short time later, again the crank moved back-and-forth in the block. We never did figure that one out.

 

Wow 1/4" is a crazy amount of end play on any small block. I MAY be .024" however the crank thrust looks good and the block saddle also is fine. 1/4" may an exaggeration but easily visible end play is waaaay too much.

 

Nice. It'll be interesting to watch you go about the build process.
I see possible target compression approaching 11:1. Think you'll go in that direction? That's aluminium heads and a big cam in my books.

 

11.4 : 1 actually which is rather high in todays world and yet the cams the 70 era Z28s used were really wide LCA like 116 and worked on pump premium, admittedly of a type we can't get today. The 64 cc head chambers and the very slight dome (-2.4cc) are problematic to be sure.

I'll most likely use everything BUT the pistons. I just now used a feeler strip and even in perfect fresh .030 bores and the pistons with zero skirt wear I get .006" piston to wall.

I absolutely enjoy spending way to much time doing an assembly especially on an engine I also built (did the math for performance/select the parts). I'll happily make a 6-8 hour assembly last twice as long and anally measure everything.
FWIW I differentiate between an "assembly" which can be bone stock and a "build" which represents mods for performance.

 

I'm of the same mind in that regard.

There's always been a distinction between an engine assembler and an engine builder. Back in the day, I had access to a very well equipped machine shop and full engine building facilities. These days, not so much. While I have every conceivable engine measuring tool at my disposal, I'm no longer in a position to measure and machine to suit. So I regard myself as an assembler. So much so that I'll spec the shortblock and all of the performance engineering that I would like to have but I've got to pay for all of the machining and even the assembly. It's not like there's anything I can do about finding that my bearing clearances are too tight or too loose and don't have a selection of bearing shells to swap around. So I leave it to whoever I've enlisted as my builder and I'll pick up my "take out" shortblock and bring it home. Cylinder heads, valvetrain (which I'm very fussy about), and all the other "bolt on" stuff is easy peasy.

But even the bench racing (like this thread) and parts procurement keeps me in the game even though any build for me will now be delayed for another few months. I could get started on the inevitable teardown and post-mortem but I'd prefer to keep the heap running under it's own steam until I'm fully ready to swap in a new shortblock (assuming that's all I'll need that is).

 

'm with you on keeping it running until your ready. I have a large single bay garage and I much prefer for my project cars to be able to run and drive out during the winter months. That way if I have another car to work on like a friends or relatives I can use the garage in 20 below. The 85 I have is running fine under its own 305 CID steam and while I will continue to work on the next engine I won't get to the install until spring. Currently It all works including heat and defrost. I really plan to make this one good and healthy but a little more all season friendly and keep it long term.

 

Strictly a three season car here. Or maybe 2 1/2 seasons as the weather dictates.
This latest project may lean towards more of a track car than the all round machine it's been. Drag racing is great and I really miss getting out. Especially since I'm now only 25 minutes from the track. But I like the cross country tours too. Friends and family in Ontario not to mention my racing buddies and the old chassis shop. It's fun to drive 3500 kms, bolt on the slicks and race. Not sure how this will morph out. The engine spec may dictate that as I'm not entirely certain which direction I'm going. Open road events have a real appeal for me too.
I'll be watching yours for sure. Possible a very similar engine approach.

 

That is the correct clearance for those TRW pistons. They taper at the top at the gauge point. That type of forging actually expands that much.

 

The hits just keep on coming!

Picked these up last week from a farmer near New Dayton Alberta...$50 Cdn.

Never used, band new flat top hypers, that from Summit, with duty (AND with an order over $300 US to get the free freight) these would have been at best $180.00 or so. He said when I asked, he bought them from a friend and he had a Lethbridge Auto Parts receipt for $240 and GST. He took his block in for machining and the 1st hole didn't clean up until .060" so the .030s wouldn't work.

He put them on KIJI as "350 pistons" no mention of Chevy, Chevrolet, SBC etc. so they were on a while and no one else stumbled across them. I got lucky.

I have already let them match the blocks temp in the garage and then checked the clearances and they are bang on . A .001 slides easily annd a .002 sticks!

Just a reminder my block is a perfect 4.030-4.035 and no ridge at all they were just done, which is one reason I bought this block.

 

Nice score. I may have to get you to shop for me!
Those are the same pistons I had in my standard 350 when I got back into the hot rodding game a couple of decades back.

 

Uh-oh, those pistons just might be the rebuilder type where the compression heights are .020" less to compensate for the assumed block decking.
If so, there goes your quench.
According to Summit Racing:

 

Hmm. I just noticed the slightly different part numbers. H345NCP vs H345DCP.
Along with a difference in compression height. 1.548" for the "D" version and 1.560" for the "N" version.

 

Yes, and the N version is no longer available.