When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
A lot of that is in the tune. And type of clutch. I havent messed with alot of manual cars tho but there are things my tuner friends do in manual cars to help drivability
A lot of that is in the tune. And type of clutch. I havent messed with alot of manual cars tho but there are things my tuner friends do in manual cars to help drivability
Probably lean it out with a lot of advance but then I think you end up with a buck.
I ran a cc306 with a 6spd in a vette with 3.54 gears back in 2006/2007 and it was terrible in like parking lots and stuff where you need to crawl around in first gear. Constantly clutching it, which is no fun.
For a 'strip' car I get it, how many parking lots are you going to be walking across, but for this car when I'm in slow traffic at the beach or taking it to work I don't wanna deal with BS.
(I know I know, why did you put a manual in it lol)
Yeah to do that while making big power you need bigger cubes great heads and a small duration high lift lobe. Small cubes ok heads just need cam to get the air
The CC305 cam, assuming my chambers end up being what I think they are, will be 11:1 compression and 8.6 DCR.
If I run the CC503 cam, 11.1 compression would be 8.75 DCR. That would probably be tough with pump gas.
Buuut. If I polish my chambers to 56cc, my static compression drops to 10.8 and DCR 8.5 with the CC503 cam. The 503 in theory will make more power than the 305. Both appear to have a crappy idle lol.
Surprised you haven't considered the ZZ409 cam w/your gearing, as well as the need for decent idle.
The reason I ask relates to my HT 383 thread. I question the ability of the OEM hardware (even brand new) to be able to handle that kind of power. If guys are spinning to 6500 without putting a rod through the block then my choices became a little bit clearer. A 4340 crank, PM rods and factory bolts sound like they would survive. Drag racing anyway. Several minutes at WOT? Still leary.
Well 383 has higher piston speeds. A 350 would have less stress but we turned LT1’s to 6800 even tho it was done by 6500. Low mid 6000’s should be fine. My buddy turned his hsr L98 to 6200-6400 often on stock crank rods
Thanks for that.
Given the heads I'll be using I imagine I'll run out of airflow early. Probably 6000 rpm max engine speed. I haven't had a cam spec'd so peak HP RPM is am unknown but I think I'll build more towards conservative than aggressive.
In the '90s I'd run stock "X" rods with ARP hardware to 6200 rpm without issues.
Rods are so cheap now I just buy the $200-260 eagle/scat/whatever rods with ARP hardware.
Even cranks, I have a ton of GM cranks in the shop and it's more expensive to cut or even polish them than it is to buy new eagle crank..
6500 RPM on a stock lower end would make me nervous though. Many have done it but I probably wouldn't.
On Jet drives we would run 6800-7000 RPM. Not for 8 seconds like a drag car, but rather running that RPM until it runs out of fuel. This is where good parts really mattered!
On prop boats everything ran 5500-5600 RPM, so stock crank + rods, even at 550-600hp was of no issue.
Then in 2010 they introduced a 45mph speed limit on Lake Winnipesaukee and that's the end of go fast boats..
The Eagle rods have proven no stronger than stock for a lot of the applications I am familiar with. In the Subaru engines I build routinely we have found that the factory rods with upgraded hardware are stronger than Eagle rods. Also, according to my machinist, the Eagle stuff has terrible finish machine work from the factory and he has to redo them all the time. I highly doubt that Eagle rods are stronger than the powdered metal Vortec rods. PM parts are often stronger than forged parts for many modern applications. I have seen it often quoted that the PM rods are good to 500 HP.
The Eagle rods have proven no stronger than stock for a lot of the applications I am familiar with. In the Subaru engines I build routinely we have found that the factory rods with upgraded hardware are stronger than Eagle rods. Also, according to my machinist, the Eagle stuff has terrible finish machine work from the factory and he has to redo them all the time. I highly doubt that Eagle rods are stronger than the powdered metal Vortec rods. PM parts are often stronger than forged parts for many modern applications. I have seen it often quoted that the PM rods are good to 500 HP.
GD
I don't do anything with Subaru so I don't know how strong their rods are.
I've used eagle and scar rods and never had a problem. The design of the the big end is better, and the forgings are from a strong alloy. I've never used the PM rods, I've heard somd say they were strong other said they are junk. Either way, I prefer bushed rods.
Anyhow, so 1.050" is legit the cross sectional limit on LT1 heads. At 1.100 you break through lol.
I've seen Eagle rods bent like a taco. And really it's not that surprising - all their forgings are from China. And the final machine work on a lot of their cranks, etc is pretty terrible. They don't dress their grinding wheels properly all the time and it's fairly common to see cranks with hourglass shaped journals that have to be reground to correct. Some have just been sent back as it wasn't really feasible to correct them. That stuff is being mass produced in China and they know that 90% of it is going to get thrown together by amateurs and high failure rate is unavoidable anyway.
Scat seems better but then my machinist says they are just about as bad. All of that crap is coming out of China for pennies and the quality is reflected in the price.
The PM rods are miles better than the old pink rods, and by simply replacing the stock hardware, are not going to fail under any non-forced induction application.
Maybe the GM 4340 forged crank isn't a bad deal. But then there's this:
Originally Posted by GeneralDisorder
The PM rods are miles better than the old pink rods, and by simply replacing the stock hardware, are not going to fail under any non-forced induction application. GD
Which is the way it's always been to me but then again my experiences, especially lately, are limited. If I can confidently take the as purchased bottom end (as in the 4340 crank and PM rods with stock bolts) keep the engine speeds under 6000 (with maybe a couple hundred RPM overspeed) and go racing, I'm in.
EDIT: And racing refers to drag racing. No endurance stuff.
Maybe the GM 4340 forged crank isn't a bad deal. But then there's this:
Which is the way it's always been to me but then again my experiences, especially lately, are limited. If I can confidently take the as purchased bottom end (as in the 4340 crank and PM rods with stock bolts) keep the engine speeds under 6000 (with maybe a couple hundred RPM overspeed) and go racing, I'm in.
EDIT: And racing refers to drag racing. No endurance stuff.
well either way, all of my connecting rods in the shop are regular stock GM rods I don't have any of the PM rods. But even if I did, the 4340 rods are a stronger alloy, the hardware design is better, and I prefer Bush rods to press-fit.
by the time you have stock rods resized, buy r-pod where, and pay the machine shop to press your pistons on you spent more than a good set of 4340 rods.
....by the time you have stock rods resized, buy r-pod where, and pay the machine shop to press your pistons on you spent more than a good set of 4340 rods.
-- Joe
That's more or less the choice I'm having
to make. I can buy a complete GM shortblock but the only real value would be its drop in and go capability. But if its not capable because of the rod bolts being a weak link then that economy goes out the window. I'll take the same approach I've done in the past and that's a conventional rebuild with my choice of hardware and send it off to the machine shop. I'm just trying to sidestep that and do a simple re and re. Then the 350 core I'm pulling out can be assessed and do with it whatever might need to be done. For the
record, it has Elgin rods. ARP bolts and a GM forged crank. The cylinders I figure are smoked and a rebore is necessary. I really would.like to keep it as a spare and ultimately a no rush engine building project for the future.
By the way, thanks for the discussion.
That's more or less the choice I'm having
to make. I can buy a complete GM shortblock but the only real value would be its drop in and go capability. But of its not capable because of the to bolts being a weak link then that economy goes out the window. I'll take the same approach I've done in the past and that's a conventional rebuild with my choice of hardware and send it off to the machine shop. I'm just trying to sidestep that and do a simple re and re. Then the 350 core I'm pulling out can be assessed and do with it whatever might need to be done. For the record, it has Elgin rods. ARP bolts and a GM forged crank. The cylinders I figure are smoked and a rebore is necessary. I really would.like to keep it as a spare and ultimately a no rush engine building project for the future.
By the way, thanks for the discussion.
I would have just bought a short block if that was an option, but I didn't see any LT1 short blocks offered anywhere.
I have a few of these motors on stands in the shop. I just, I dunno something in the back of my head told me I need to keep the original 4 bolt main Y-body block in this car so I had it machined.
I think I'm gonna do an eagle crank and scat rods. I gotta check my crank, but I'm willing to beat it's boogered.
Block is done. $650 to bore, hone, and deck it to 9.00".
They don't have a machine to balance cranks though, so I gotta figure that out. I'm still on the fence - do I do the scat crank + rods, or just buy rods and re-use my crank.
Machine shop thinks I should re-use my crank and rods since it's not a race car, and just do the oversize pistons and call it a day.
I have a '97 LT1 in the shop which should technically have PM rods. Now I'm kinda tempted to take the crank and rods out of that. If I did use the stock crank + rods, the pistons would only be lighter by 20 grams which is under the recommended threshold (1oz) for re-balance.
Did you not line-hone it? The factory main line bore is notoriously all over the place - to the point that GM used various bearing inserts that were +/-.0005" to get the clearances right. You can't order a standard set of bearings and expect the clearances to be correct using only a single box. I can't stand that, so I always line hone used blocks.
I would use the crank after a magnaflux, and then use the PM rods from the 97 block with ARP hardware. Crank and rods sized to each other with new hardware and balanced of course.
GD
Last edited by GeneralDisorder; 01-24-2019 at 05:29 PM.
Did you not line-hone it? The factory main line bore is notoriously all over the place - to the point that GM used various bearing inserts that were +/-.0005" to get the clearances right. You can't order a standard set of bearings and expect the clearances to be correct using only a single box. I can't stand that, so I always line hone used blocks. GD
. You can't order a standard set of bearings and expect the clearances to be correct using only a single box. ..
GD
One of the reasons why I elect to have my machine shop assemble the shortblock. I have every measuring tool imaginable available to me but they don't do a lot of good if you can't get there from here.
One of the reasons why I elect to have my machine shop assemble the shortblock. I have every measuring tool imaginable available to me but they don't do a lot of good if you can't get there from here.
Yeah that's how GM did it. I've just never liked this idea because even if you get the clearances the same, it does still mean that there is likely some alignment issues between the main bores. Often you have to install a single bearing (half) that is under/over to get the clearances right and it's just a sketchy way to do it IMO. A good machine shop should be able to line hone the mains and hit exactly. 002" with a single box of standard sized bearing inserts. I don't see a reason to not correct this production deficiency if you are going to the trouble of a rebuild.
Did you not line-hone it? The factory main line bore is notoriously all over the place - to the point that GM used various bearing inserts that were +/-.0005" to get the clearances right. You can't order a standard set of bearings and expect the clearances to be correct using only a single box. I can't stand that, so I always line hone used blocks.
I would use the crank after a magnaflux, and then use the PM rods from the 97 block with ARP hardware. Crank and rods sized to each other with new hardware and balanced of course.
GD
I had intended on align honing the mains but he checked and said they were absolutely perfect. I know a lot of the 70s blocks were all over the place. The Vortec blocks that I've used all seemed fine, and apparently my 4 bolt LT1 block was perfect.
So he checked the crank today, it's straight and ok other than needing a polish and radius. The problem here is re-using the crank and some stock rods become an economic hurdle.
Polish and radius crank $125
Recondition rods $160
Press pistons on rods $150
ARP Rod bolts: $66
Hyper pistons $112 /set
Rings $35
Bearings $125
Total: $773
A complete rotating assembly from Summit with new rods, steel crank, ARP hardware, hyper pistons, bearings, rings, and BALANCED is $650
I . The problem here is re-using the crank and some stock rods become an economic hurdle.
Polish and radius crank $125
Recondition rods $160
Press pistons on rods $150
ARP Rod bolts: $66
Hyper pistons $112 /set
Rings $35
Bearings $125
Total: $773
A complete rotating assembly from Summit with new rods, steel crank, ARP hardware, hyper pistons, bearings, rings, and BALANCED is $650
-- Joe
Interesting math. And not unlike what I'm contemplating now. Buy a new assembled short block. Buy new parts and build my own. Or recondition what I have. Or a mix of last two options. I've gone back and forth between a new HT 383 shortblock, reconditioning the tired 350 ( lots of good and balanced parts there ) and now I've been challenged with piecing together a reciprocating assembly (all forged stroker) and either another block ( preferred) or the existing 70's vintage piece. Having my machine shops pricing guide would ne really helpful however I don't believe such a thing exists.
Thanks for that info though Joe.
I had intended on align honing the mains but he checked and said they were absolutely perfect. I know a lot of the 70s blocks were all over the place. The Vortec blocks that I've used all seemed fine, and apparently my 4 bolt LT1 block was perfect.
So he checked the crank today, it's straight and ok other than needing a polish and radius. The problem here is re-using the crank and some stock rods become an economic hurdle.
Polish and radius crank $125
Recondition rods $160
Press pistons on rods $150
ARP Rod bolts: $66
Hyper pistons $112 /set
Rings $35
Bearings $125
Total: $773
A complete rotating assembly from Summit with new rods, steel crank, ARP hardware, hyper pistons, bearings, rings, and BALANCED is $650
-- Joe
I don't see how a crank from a block with sometimes over 100k mi turning inside that same block is now going to freeze up or become damaged w/o a align hone. Yes there is a use for align honing/boring the block but your not only moving the crank higher in the block which in turns loosens the timing chain but wastes money on street motor rebuild.
I'm not going to aling hone my LT1 block because I'm reusing the same crank that was in the same block for over 100k mi. I'll save that $200 for better rods, pistons and new stock timing set.
I don't see how a crank from a block with sometimes over 100k mi turning inside that same block is now going to freeze up or become damaged w/o a align hone. Yes there is a use for align honing/boring the block but your not only moving the crank higher in the block which in turns loosens the timing chain but wastes money on street motor rebuild.
I'm not going to aling hone my LT1 block because I'm reusing the same crank that was in the same block for over 100k mi. I'll save that $200 for better rods, pistons and new stock timing set.
My 2 cents, take it or leave it!
Some of the blocks are off. I'm not sure about LT1's. My feeling is mainly the mexican production blocks and stuff. There was certain casting numbers we used to look for back in the day, I think like 518 and such that were good blocks. Rumors of high nickel and all that, but the key was when sonic testing and measuring they were pretty darn good starting points.
I'm going with the eagle rotating assembly because it's a matched set, and more economical. This is probably why I have a shop full of cranks and connecting rods.
So anyhow. I've been going through heads. I ported up a set of '324 castings to 1.050" cross section, tapered everything nicely and cleaned up the bowels.
I also have a set of '561 casting off a '97 I took off earlier. I'm gonna probably disassemble them and do the same thing, then decide which pair I want to use. I hear the '561 flows better in stock form. The '324 can be ported farther, but frankly I'm not Lloyd elliott and nor do I have a flowbench. I already broke through the casting on another set trying to get it square like an AFR 190 runner lol.
Now I'm trying to figure out whats the biggest valve I can put in so I can send whichever set out to get a valve job. The valves are actually shrouded quite a bit due to the chamber design and there is not much that can be done, but maybe bigger valves isn't a terrible thing anyway.
Some of the blocks are off. I'm not sure about LT1's. My feeling is mainly the mexican production blocks and stuff. There was certain casting numbers we used to look for back in the day, I think like 518 and such that were good blocks. Rumors of high nickel and all that, but the key was when sonic testing and measuring they were pretty darn good starting points.
I'm going with the eagle rotating assembly because it's a matched set, and more economical. This is probably why I have a shop full of cranks and connecting rods.
So anyhow. I've been going through heads. I ported up a set of '324 castings to 1.050" cross section, tapered everything nicely and cleaned up the bowels.
I also have a set of '561 casting off a '97 I took off earlier. I'm gonna probably disassemble them and do the same thing, then decide which pair I want to use. I hear the '561 flows better in stock form. The '324 can be ported farther, but frankly I'm not Lloyd elliott and nor do I have a flowbench. I already broke through the casting on another set trying to get it square like an AFR 190 runner lol.
Now I'm trying to figure out whats the biggest valve I can put in so I can send whichever set out to get a valve job. The valves are actually shrouded quite a bit due to the chamber design and there is not much that can be done, but maybe bigger valves isn't a terrible thing anyway.
-- Joe
I'm not sure you want to put bigger valves in those heads. Had 2.00 int and 1.55 exh put in mine and the 2.00 stick out of the chamber a tiny amount though they did shave the heads 0.010". The build sheet said to cut the heads 0.030" but can see now why they didn't. Anyways the shop owner said they would clean up the chambers but didn't and the surface is rough as 100 grit sand paper. To late now for me to do it but had I known they wouldn't get it done I could have done this myself before the new larger valves were installed. I still consider having the shop try is as man that surface is rough. Hind sight is spilled milk but I should had the written on the build sheet. Sorry I can't remember the casting number of mine but I will try to attach pix of the heads w/larger valves if I can find it. Myself I don't think those heads needs any porting as they flow nearly 220cfm as is. The shop did clean up the blowls (that should make someone happy ) and something similar to pocket porting. So for the short duration camshafts I use I'm not worried about a flow restrict but more so flow velocity.
Not sure why my pix upload but don't attach. So I try to attach after I post this.
I'm not sure you want to put bigger valves in those heads. Had 2.00 int and 1.55 exh put in mine and the 2.00 stick out of the chamber a tiny amount though they did shave the heads 0.010". The build sheet said to cut the heads 0.030" but can see now why they didn't. Anyways the shop owner said they would clean up the chambers but didn't and the surface is rough as 100 grit sand paper. To late now for me to do it but had I known they wouldn't get it done I could have done this myself before the new larger valves were installed. I still consider having the shop try is as man that surface is rough. Hind sight is spilled milk but I should had the written on the build sheet. Sorry I can't remember the casting number of mine but I will try to attach pix of the heads w/larger valves if I can find it. Myself I don't think those heads needs any porting as they flow nearly 220cfm as is. The shop did clean up the blowls (that should make someone happy ) and something similar to pocket porting. So for the short duration camshafts I use I'm not worried about a flow restrict but more so flow velocity.
Not sure why my pix upload but don't attach. So I try to attach after I post this.
Which casting were those, could you find out?
I have a set of the 561 and 324 in my shop. I ported the 324s. I was gonna do the 561's tonight. I feel weird about putting heads with 100k miles back in with just a lap, I feel like a 3 angle valve job and new valves is a safe bet, and might as well do the larger valves.
Still trying to sort though the hogwash on the camaro forums to determien if the 561 or 324 is a better casting to use with the minimal porting I did.
Does anyone know how to CC a runner? Like I feel like you exclude the bowl volume somehow or the numbers would be misleading.
Advanced induction has the fastest stock casting based lt1 cars that i know of and they do it on 2” valve
I think they use the '324 castings, but those guys have a CNC program that gets every bit possible out of that head. I just shoot for a target CS, clean it up and call it a day. If I was doing a race build I'd just buy AFR heads.
I gotta find some time today to figure out what cheap valves will fit these heads.
I have a set of the 561 and 324 in my shop. I ported the 324s. I was gonna do the 561's tonight. I feel weird about putting heads with 100k miles back in with just a lap, I feel like a 3 angle valve job and new valves is a safe bet, and might as well do the larger valves.
Still trying to sort though the hogwash on the camaro forums to determien if the 561 or 324 is a better casting to use with the minimal porting I did.
Does anyone know how to CC a runner? Like I feel like you exclude the bowl volume somehow or the numbers would be misleading.
-- Joe
I won't get to my storage for a while but the heads are 1994 vintage. But I don't feel anything about saving money using them again having driven with them myself. Now I got new larger valves with great springs and a good clean deck. Just wish I had polished the chambers like I had expected and I may still pursue that..
How much flow do you need? 220 cfm is pretty good for a stock like 350 though I can't tell whether you went for the 383 stroker or not. And I'm sure you know the iron LT1 head flows more than the aluminum and they are overlooked in the boneyards.
IMHO no porting is needed but just cleaning up the port and blending the bowl/guide boss will add port volume w/o slowing port velocity. I think your trying to hard for an economy rebuild. Yea the LT1 forums are so opinionated and so many scab vendors that get away with personal attacks it makes the forums almost useless for what your looking for.
I've never measured the runners but you can find people that do on U-tube and it looks fairly simple. Just search for porting sbc heads. I can't recall the name of the guy that does a lot of sbc porting on U-tube but I recall he included the bowl area/volume. I measure the chambers as I'm more worried about compression ratio.
Nothing major. I usually buy aftermarket or have someone do them. Setting up valvetrain i do. Machine work i dont
I really messed up a few years ago when my buddy retired, I should have bought his machines. Kick myself. I like using equipment. Makes me feel accomplished.
Anyhow, I wasn't sure if you or anyone has ever used manual seat cutters. Obviously not as fantastic as a serda, but for just touching up a seat might not be bad.
I won't get to my storage for a while but the heads are 1994 vintage. But I don't feel anything about saving money using them again having driven with them myself. Now I got new larger valves with great springs and a good clean deck. Just wish I had polished the chambers like I had expected and I may still pursue that..
How much flow do you need? 220 cfm is pretty good for a stock like 350 though I can't tell whether you went for the 383 stroker or not. And I'm sure you know the iron LT1 head flows more than the aluminum and they are overlooked in the boneyards.
IMHO no porting is needed but just cleaning up the port and blending the bowl/guide boss will add port volume w/o slowing port velocity. I think your trying to hard for an economy rebuild. Yea the LT1 forums are so opinionated and so many scab vendors that get away with personal attacks it makes the forums almost useless for what your looking for.
I've never measured the runners but you can find people that do on U-tube and it looks fairly simple. Just search for porting sbc heads. I can't recall the name of the guy that does a lot of sbc porting on U-tube but I recall he included the bowl area/volume. I measure the chambers as I'm more worried about compression ratio.
I spoke with Lloyd last night. He gets 260 cfm out of opening the runners, bowl work, and stock 1.94 valves. That's essentially what I've done. My runners are opened up to 1.050", the bowls are worked. I don't have a flow bench obviously, but they look really good. I also ground down the boss for the guide and put a taper in it to help the flow curtain. So I dunno. I feel like I should at least freshen up the seats. But I suppose a brand new set of 1.94/1.50 valves and a lap will be ok too.
Here is the deal. It's 15 degrees out, yet we've have zero snow so I can't go sledding. My girlfriend is taking off on a cruise for 2 weeks and I decided to stay home. So I need something to keep me busy in the shop.
I had intended on align honing the mains but he checked and said they were absolutely perfect. I know a lot of the 70s blocks were all over the place. The Vortec blocks that I've used all seemed fine, and apparently my 4 bolt LT1 block was perfect.
So he checked the crank today, it's straight and ok other than needing a polish and radius. The problem here is re-using the crank and some stock rods become an economic hurdle.
Polish and radius crank $125
Recondition rods $160
Press pistons on rods $150
ARP Rod bolts: $66
Hyper pistons $112 /set
Rings $35
Bearings $125
Total: $773
A complete rotating assembly from Summit with new rods, steel crank, ARP hardware, hyper pistons, bearings, rings, and BALANCED is $650
-- Joe
How did he check for alignment ?? I had an engine come in with 400 miles on it the customer said the engine builder said the main line was perfect. HMMMM
How did he check for alignment ?? I had an engine come in with 400 miles on it the customer said the engine builder said the main line was perfect. HMMMM
I suspect a straight edge and feeler gauges, as that's how I was taught but the dude has been doing this since 1963 so he may have other ways.
01-18-2019, 12:55 PM
) and something similar to pocket porting. So for the short duration camshafts I use I'm not worried about a flow restrict but more so flow velocity.
