Got me a little LB9 in my '89. I'm in the planning phase of my engine work and I'm considering many things - however, the block must stay - I want to keep the matching numbers even if it limits my performance; it's all part of the plan for this project.

Regarding a 305 block, what is realistic for boring the cylinders? Are they much different than the 350's with regard to core-float or wall thickness?

And what is the low-down on stroking a 305? From what I have learned about 350's, doing a 383 stroker requires some block machining on the underside for crank clearances that doesn't seem too drastic - similar with the 305 or not???

Thanks,
Kevin

 

Wall thickness is around the same for a 305 and a 350, meaning you can go to about .060 over without too much problem. Core shift that i've seen doesn't seem any worse between the 2.
As for stroking, it's pretty much the same prodecure between a 305>335 as a 350>383. Best bet is to get a complete rotating assembly so you don't have to worry about balancing it.
Also, i'd only go .030 over the 1st time around leaving room for future rebuilds.

 

I couldn't have said it any better myself

 

Ok guys - sounds great for the short block. Now I need to figure out who produces stroker kits of top-notch quality for a 305.

TunedPort335 - can you say more about your engine? If you'd rather e-mail me, feel free to do so. Did you do the assembly your self, or did you have a specialty-shop do it? I would really like to know more about what you decided to do with induction and engine management, electronically speaking that is...

EDIT, EDIT - just went to your CarDomain site - explains alot, should have looked there first....... But please do comment on how the whole project has done - headaches, reliability issues etc. Thanks

Anyone else here stroke out a 305??

K

 

I built the motor myself when I was 14, with guidance from my father. The biggest headache for us was clearancing the block for the extra stroke. We used a feeler gauge to measure how much clearance we had, and once we were satisfied...we put the motor together. Make sure you triple check EVERYTHING if you are building it yourself. You'll be happier in the longrun.

Induction = Untouched TPI for now, would like to change in the future though.

Computer = Just a hypertech chip, nothing special so far. This will also be custom in the future.

It's running through stock heads, stock intake, hyperjunk chip, stock fuel pressure and little 19lb injectors. It laid down 347rwtq through the exhaust on a 95* day...so It's fairly healthy. It's going to be my daily driver in the spring, so I didn't want nothing radical.

The best kit for your money will be the Powerhouse kit (the one I used). The Speed-O-Motive kit appears to be a little more expensive, and it uses shorter 5.565" rods. In any application, especially a stroker application... you want to use longer rod to keep piston speed down. My powerhouse kit came with 5.7" rods, which is the reason why I beleive it is better. I also had them balance the bottom end, new flexplate and balancer, CR3 shotpeened rods with ARP bolts, Moly Rings, and a full engine gasket set. It all came to $993 shipped to my door.

If you got anymore questions just ask.

 

335,

When are you getting that thing dynod in 3rd gear? I hate to sound like a broken record here, but I'm dying to know what that little stroker puts out.

Robert

 

Well the car should be back from the bodyshop in a couple days, its already been painted. Then I need to do a few things over the rest of the winter, and buy some new rear tires.

Once the tires are on, its go time. I still need to cut the bottoms out of my airboxes... :lala:

 

As long as the dyno operator sets the dyno up right, the runs will be very close to being the same, with the exception of more sample points in the longer gear run. Max HP and TQ will remain the same between runs. The only thing that will change is that the plots will appear smoother from more data samples...

 

Thanks for the info 335. Great site at CarDomain too - keep it up.

I'm impressed with your work being a younger guy too - very cool. Kudos.

My goal for now - what will make me happy after and engine build - is 1hp per cube while keeping it naturally aspirated. I'm trying to decide if I want to do this with 305 cubes, or 335 utilizing a stroker. I don't know if it's possible or not, but I'm trying to gather as much info as possible to see how realistic it might be. Sounds like with a stroker and using head, intake and management changes that are fully optimized might make this a reality for me. Feel free to comment - anyone. Just don't tell me to get a 350 - won't happen for this car. End of discussion on that. I like the uniqueness of the 305 and plan to just see what I can do with it for the challenge of it.

K

 

I disagree. I did one run in 3rd gear, had to shut down early... made 224rwhp and 347rwtq. Next run I made in 2nd gear, mad 209rwhp and 311rwtq. BIG difference between gears.

Think about it like this, 2nd gear isn't a 1:1 ratio like 3rd gear....so its almost as if you are "slipping" the tranny when doing a dyno run in 2nd gear (as compared to 3rd). 3rd gear is direct, and results in visually higher numbers. I got a magazine article around here somewhere, they dynoed 2nd, 3rd, and 4th gear with a LS1 Camaro. 4th gear made the highest out of all of them.

But anyways, back on topic

 

You can definitely make 1hp per cube with a 335 or a 305 for that matter. Look at my motor, its approx 300-305hp crank and 434tq at the crank. I still had a stock catback with a Flowmaster muffler, stock heads, stock untouched TPI, 19lb injectors, and I haven't even taken out the bottoms of my airboxes like I said earlier. Now with my 3" hooker catback, bottoms of airboxes cutout, and new TPS and IAC it should run alot stronger and better.

Either way you go, 335 or 305, if you chose your parts wisely and match them all up... its very easy to get 1HP per cube. Put a nice set of SLP runners, ported base, and ported LB9 heads, along with a nice camshaft and I think you'd be well on your way to your goal

Check out this thread- https://www.thirdgen.org/techbb2/sho...62#post1638162

He's running the same cam I got, with untouched TPI.

 

Chris - right?
Thanks a ton for that link - that is very encouraging for me to say the least. I was intending on head work/alternate heads, probably a complete balancing job, a bit more aggressive cam, intake porting work with runners, exhaust work, and management tuning to really polish off the system as a whole, maybe some pulleys etc to optimize output - pretty basic stuff when you really look at it - and it sounds like with all that 1hp per cube is rather easily attainable - verrrry cool.

Speaking of that cam, who's the manufacturer? Also, can you please comment on how rough it is at idle? Supposedly the cam in my IROC, due to the manual trans combo option in '89, is as follows - Duration: int 207, exh 213; Lift: int .415, exh .430 with 117 degrees separation. It's real smooth with just a hint of rumble to it from the exhaust note. I haven't confirmed those numbers but they're from this site so I'm trusting them for now..... So how smooth or rough is your cam to what you had before?

I've read that a cam change with Mas Air on a TPI would require computer tuning to really optimize things - do you think with some computer tuning you will get even more out of that cam of yours?

Kevin

 

Sounds like you've been doing a good bit of research. You're 100% correct. With basically any cam upgrade, the best thing you could do is get a custom chip burnt for your car. The Hypertech will help a little...and thats about it. I've seen some instances where guys gain anywhere from 10-30hp just from a custom tune alone. It's well worth it, and is something I plan on doing after I do heads & intake.

The manufacturer of the cam is Comp Cams. It's known as a Comp Cams "264". The specs are 210/220 duration at .050 lift, .480/.480 lift, 112LSA, 108 intake centerline. With a cam like this, you'll obviously want to upgrade to some stiffer springs. Comp Cams techline pointed me in the right direction when I was choosing mine.

As for the sound, well I think it sounds fairly lumpy. It's nothing radical, but its enough to get noticed. Here's some soundclips of my car-

Idle through Flowmaster (right click - save as)

Idle through open cutout (right click-save as)

 

The difference is that an automatic trans slips less in the lower gears. The dyno isn't at fault because it just reads RPM vs. Time. If you have a tight converter, the dyno will read the same, no matter which gear it's in. Loose converters will spike the readings when the throttle is nailed up to the point where the converter locks up though, so in that instance it would make a difference.

Auto transmissions just lie a lot.

 

I have a stock converter (a tight converter). The dyno didn't read the same, and didn't create any spikes.

First run 3rd gear - 224rwhp 347rwtq shut down early
2nd run 2nd gear - 209rwhp 311rwtq

I've seen many cars dyno, probably anywhere from 40-50 in person. When the auto's downshift by accident (from starting at too low of an rpm, causing it to downshift when floored), the numbers are always lower than they are in 3rd gear.

 

if you want to keep the numbers matching, why are you considering other heads than the ones that cam with the car? The head casting numbers are just as important in a "numbers matching" resto. I did one of those on a 70 Hemi Superbird, and i'll never do it again, detailed down to the factory chalkmarks on the chassis. PITA...every car since then has been a resto/mod. Just somethin to think about.

 

You point is well taken and one that I am considering too. I keep going back and forth between the ideas of straight-up restoration vs. lightly modified or I guess as some now call it a "custom restoration". When you come to the suspension on these cars, if you want to improve performance we all know that you have to go to the aftermarket - I already have gone to a Spohn track bar and BMR trailing arms with poly bushings on the sway bars - that falls under the "custom" resto category in my book - I've done it already.

So I'm trying to decide if I should carry that philosophy ahead to the engine as well, or if I should really keep it matching perfectly. If I wanted to keep thing original I could pull the engine, have the heads fully worked over by a reputable shop, maybe install new improved-over-stock valvetrain components and have the rotation assembly balanced - stufff like that just staying with the original fundamental parts to the engine - and just call it good for this car. Frankly, because it's an IROC and I truly believe that some day they will be quite valuable I'm trying not to make bad decisions right now to affect it's value down the road. Decisions, decisions........

Another example is I'm also currently dealing with a wheel dilemma - this car of mine is really no good for a "turn and burn" approach to driving with 15s - If I go aftermarket, obviously an outwardly visible non-stock item. I could go for a set of 16s in the stock style and get 'em refurbed for this car but then those are 16s too - not as performance oriented and 17s.

As you can see I got some serious thinking to do - but I still need your all's input - its very valuable in my planning process.

Thanks again,
K

 

Well, you always have the option of just storing the engine/heads/suspension pieces, and as long as you don't permanently make any modifications, you can always go back to stock stuff. I've sold about 3 resto/mod cars, and never had any trouble selling them, especially when i told them i had the stock pieces in storage, they actually offered me more when i told them that, not that they weren't offering enough before, though. Actually, the restified 70 Superbird I did is still sitting in the local Chrysler dealer's showroom, he bought it off of me the first day after I had it painted, right after i put the roadrunner decals on it, he said it was fine with the minor mods, as they weren't permanent, and i gave him the stock pieces.

 

That is also a good point about hanging on to the original parts. And when you think about it, muscle cars from the really collectable years in the 60's across all brands that are custom restos are bringing big buck now days. Porbably in the general hot rod market. I do believe that the really rare all original cars are worth more but that is to be expected too - they usually are really rare items with some very unique characteristics. My IROC I like to think is or will be rare but it's no 1LE or B4C or anything like that. Perhaps from that point of view a custom restoration would suit me well. I like the discussion though - helping me to think things over.

Here's another question - how much increase in performance could I gain by just a blueprinting/balancing of the engine and using very high quality replacement parts? I could fine tune the engine to the n-th degree staying within the boundaries of stock specs - what would that potentially result in? Let's just leave out the financial/cost/benefit factor just for the sake of discussing the potentials of this idea.

K