brp88gta

Hi guys,

I was hoping you guys could help steer me in the right direction. I have a 88 GTA with a 305 TPI auto which has a cracked block. I would like to build a visually 100% stock appearing L98. I have restored the car back to factory stock years ago and I would like to keep it appearing that way.

That being said, I understand what is needed to change to the 350, but I was looking for opinions on what cam would be best in a stock l98? I would like to get as much out of the motor as I can while still keeping factory exhaust manifolds and intake. I'm willing to port the intake and add a afpr if needed. Obviously i would also tune it as well.

I from reading this forum, it seems like a lot of people have used the crane 2032 cam for close to stock motors, but my concern is that this cam, while sounding cool, will hurt performance and driveability with an other wise stock motor. Does anyone have any experience with this cam in an otherwise stock engine?

I am fine with going with the stock l98 cam or lt1 cam if that is the best choice, but I wanted to see if there were any other good options out there that would give me a little more power/sound without modifying anything that is visual outside the engine or hurting performance. Let me know what you guys think.

Thanks,
Brian

Orr89RocZ

iTrader: (20)

I dont think the stock head intake L98’s respond well to cam swaps. Theres only alittle bit of power in them

I did a cam only rebuilt L98 with long tubes and dual 2.25” exhaust. It only made 224 whp which is maybe 10-15 more than alot of other stock L98 numbers i have seen but some have dyno’d closer to 215-220 so the cam and exhaust surprisingly didnt seem to do much

Cam was a comp grind that I think was a 218/224. But it could have been 212/218 grind, but it sounded like a 218. Either way, once tuned it was fine. It did take alot more tuning than other setups i have done which also was surprising since it was mass air flow. But drivability was great, no problem with brakes or anything like that

Abubaca

iTrader: (3)

How much are you willing to do? What about budget? Goals? I ask because the biggest performance mod I made wasn't motor related. Well....at one point anyway...now it's quite different. Anyhow, it was gears and a torque converter, both parts that would obviously pass a "stock appearing" test.

...I agree with Orr...those heads....bleh. I think the intake restricts upper RPM and ultimate peak dyno numbers, but it can still make for a fun torquey street motor.

Orr89RocZ

iTrader: (20)

Yup intake mods to get flow and or rpm is needed to make power. No sense in a big cam that needs more flow or rpm to make power when engine cant deliver

I had intake swaps make more gains than the small cam or so it seems from the only cam only L98 i did, vs 2 other full bolt on stock head stock cam L98’s. My intake swap bolt on l98 did 254 whp on lean tune. Would have been 260-265 richened up some

Drew

iTrader: (58)

Cast iron L98 heads can't be that bad, GMPP used them on a "320hp" crate engine back in the day. Strap on a TPI, emissions friendly manifolds, and so on and the number tanks. A stock L98 with all the stock go-fast goodies is still fun to drive and faster than 90% of stock and lightly modded thirdgens on the roads.

By the numbers, the 89 roller cam was the most aggressive of the stock TPI cams. A little more cam probably isn't going to hurt much, but if you're going to stick with the stock TPI and stock manifolds, what's the point in a bigger cam?

I ran a flat tappet Summit cam in my 86, which was basically a L98 clone built on an earlier block, flat tops, L98 iron heads, SLP headers. Pretty sure it was this one - https://www.summitracing.com/parts/sum-k1103/ It made for a bit of a beefier exhaust note, but not really a lumpy idle. Ran fine with the stock 305 computer, injectors, etc. Made tons of torque from idle until the TPI plugged up the works. Doubt it made impressive HP numbers, but it was fun to drive and you could tell it had a wee little camshaft. Best? No. Fairly well matched to the limitations? I think so.

dmccain

iTrader: (2)

I agree with these guys. Find a stock #049 1989 model GM roller cam. 207 213 duration 415 431 lift. I think it was also used in Corvettes a few years around there. Crane 2032 I hear is also a great computer friendly cam also. L98s are strong engines bone stock. Im about to be acquiring one myself I cant wait. My friend kept having issues with his TPI system years ago and did nothing but put a 650 carb and edelbrock intake and hit high 13 sec 1/4 trips afterwards. Previously it was a mid 14 sec car.

brp88gta

Thanks for all of the responses guys.



I guess I should have clarified more on my goals. My main goal is to keep it completely stock appearing. Since the original block is cracked I figured I would rebuild a 350 for it. Since I will be replacing the cam regardless, I just figured I would see what you guys recommended. I'm looking at it as an opportunity to make the car a little more fun while I am at it. While it would be nice to have something that has a nicer exhaust note than stock, I don't want to have a mismatched setup that will not run well and hurt power. If the stock l98 cam is my best bet, I will go with the stock cam.

Drew- The summit cam seems like it is close to what I'm looking for. A little nicer exhaust note and something that wont hurt power or drive ability. However I would like to stay with a roller cam.

Drew

iTrader: (58)

Yeah, definitely run a roller block. I didn't have that luxury at the time. I mentioned the flat tappet cam as more of an experience with a small cam than a specific suggestion.

Go Blue

The other thing that you can do is use 1.6 roller rockers on your intake valve and 1.5 or 1.6 on your exhaust valves. That helps the engine breathe a little better as well.

zya5point0

iTrader: (4)

If you're willing to give up the bone stock look for almost bone stock you could throw some SLP runners on it? Still would look close to original, but you'd have a lot more potential. Just something to think about.