CorvetteForum - Chevrolet Corvette Forum Discussion

CorvetteForum - Chevrolet Corvette Forum Discussion (https://www.corvetteforum.com/forums/)
-   Engine Mods (https://www.corvetteforum.com/forums/engine-mods-7/)
-   -   L82 Cam questions (https://www.corvetteforum.com/forums/engine-mods/4080553-l82-cam-questions.html)

Novaette 12-19-2017 08:37 PM

L82 Cam questions
 
While I don't have a Corvette, my car does have a few Corvette parts(cam, 290hp350 and 67 master cylinder) so I how that make me accepted lol.
I have a 290hp 350 in my 65 Nova, has Weiand Stealth intake, and 600 Summit carb, stock rams horn manifolds and duel exhaust. Th350, stock converter, shift kit, 3.08 gears 215/60 15 tires. I'm looking for more info on the L82 cam, specifically all the timing specs. Can't seem to seem them. Is the cam ground straight I'm up or is the advanced? Would advancing the cam 4° help low end at all? Im not really wanting to change the cam, but would like a little more bottom end. I do plan on adding either some Doug's Tri-Y headers, or some fenderwell headers, along with a set of heads(Vortec or 170-180CC Aluminum). I don't want to change the converter either. Jus optimize what I have. Thank you.

Kevova 12-21-2017 04:32 PM

IDK where you would get a cam card for a GM L82 cam. Factory cams are normally straight up, aftermarket can vary. Advancing cam will help with bottom end. Tri Y would be the better choice in headers. Different rear gear would help also....something around 3.50. You should change gear before investing in converter.

Novaette 12-21-2017 08:56 PM


Originally Posted by Kevova (Post 1596226549)
IDK where you would get a cam card for a GM L82 cam. Factory cams are normally straight up, aftermarket can vary. Advancing cam will help with bottom end. Tri Y would be the better choice in headers. Different rear gear would help also....something around 3.50. You should change gear before investing in converter.

I found the installation instructions for the motor, they state the cam is ground straight up. Unfortunately I'm on a budget, and it does not allow a gear change, and the car is my daily driver that does see some highway time, so a gear change would not be in my best interest, at this time. I have really thought about the tri-y and think ill go that route. I bet just the timing change and headers will get me to where I want. Since this is a father and son project I have thought about pulling the heads, going to a thinner head gasket, and going to 1.6 rockers. Thanks for your help.

Kevova 12-22-2017 09:15 AM

You should " map out" your goals. Many times engines get modded only, leading to poor overall performance. If it's a daily driver and a gear change is not happening, focus on performance below 5000 rpm. Better cylinder heads even if there iron and not aluminum are worth looking into. The cam will work better if engine is at least 9.5+ to 1 compression.

Novaette 12-22-2017 10:10 AM


Originally Posted by Kevova (Post 1596230519)
You should " map out" your goals. Many times engines get modded only, leading to poor overall performance. If it's a daily driver and a gear change is not happening, focus on performance below 5000 rpm. Better cylinder heads even if there iron and not aluminum are worth looking into. The cam will work better if engine is at least 9.5+ to 1 compression.

Correct. I believe the key is the heads, both compression and flow. Vortec seem to fit the bill pretty well. Are there any other budget friendly that would be a better street head?

Kevova 12-22-2017 12:22 PM

You really need to know how your 350 is put together. Engine code stamped on passenger side of block deck may give you an idea of what you have. The L31 Vortec heads which are widely available used, have to be modified to fit your intake. GMPP sells Vortec heads that accept sbc intakes. World products sell SR (stock replacement) also White Performance offers budget minded heads. Local machine shops can sometimes be a source of good heads that weren't picked up or customers selling the old parts because they are upgrading. "Need to sell the old stuff to buy the new stuff to go faster" I would avoid center bolt valve cover style heads if possible. If you plan to run roller rockers you want them set up for screw in studs. The C3 parts section may be helpful. You need to find out what pistons are in your engine to know what head you need. You could check the casting numbers or marks of your heads to see what you have.

Novaette 12-22-2017 12:49 PM


Originally Posted by Kevova (Post 1596231985)
You really need to know how your 350 is put together. Engine code stamped on passenger side of block deck may give you an idea of what you have. The L31 Vortec heads which are widely available used, have to be modified to fit your intake. GMPP sells Vortec heads that accept sbc intakes. World products sell SR (stock replacement) also White Performance offers budget minded heads. Local machine shops can sometimes be a source of good heads that weren't picked up or customers selling the old parts because they are upgrading. "Need to sell the old stuff to buy the new stuff to go faster" I would avoid center bolt valve cover style heads if possible. If you plan to run roller rockers you want them set up for screw in studs. The C3 parts section may be helpful. You need to find out what pistons are in your engine to know what head you need. You could check the casting numbers or marks of your heads to see what you have.

The engine is a 290HP 350 crate engine. I bought the car with the engine installed, have the recipts and know the previous owner and the shop that installed the engine. I will keep my eye out in the parts section. Thank you.

Kevova 12-22-2017 02:19 PM

I must of missed the crate engine part. The GM 350 290hp engine is 8-1, with 76cc head, and the cam is similar to the L82.
You should be looking for 1.94 1.50 64-60cc head it will get you 9.5-9.75 compression ratio and should keep you on pump gas regular or mid grade depending on tuning. Long slot 1.60ish stamped steel rockers are a thrifty alternative to the rollers when you change heads. I'm not sure the increased lift from the 1.6 rockers will help on a 8.0-1 engine without a blower. Rollers can always come later.

Novaette 12-22-2017 02:26 PM


Originally Posted by Kevova (Post 1596232849)
I must of missed the crate engine part. The GM 350 290hp engine is 8-1, with 76cc head, and the cam is similar to the L82.
You should be looking for 1.94 1.50 64-60cc head it will get you 9.5-9.75 compression ratio and should keep you on pump gas regular or mid grade depending on tuning. Long slot 1.60ish stamped steel rockers are a thrifty alternative to the rollers when you change heads. I'm not sure the increased lift from the 1.6 rockers will help on a 8.0-1 engine without a blower. Rollers can always come later.

Would the iron heads used for circle track racing be a good choice? Speedway has all kinds of very small chamber heads. The rockers would increase lift to around 480/490. I have read so much about the stamped rocker arms are not worth it. I don't see how, the lift gain alone, has to net something, even if keeping friction the same. I read a little hear and there about L98 heads, are they easy to find? Are they a good choice? Again thanks for the help.

Kevova 12-22-2017 03:09 PM

Because of your application oval track, 113 l98, 175-195 cc heads should work. You don't want ports or lift that is too much where torque is lost. The stamped steel long slots 1.65 did a pretty good job for decades before rollers came down in price. There is a benefit to rollers, they reduce friction and wear. They also require additional attention when installing so that roller tip is centered on valve tip, if not bad things can happen. I would be careful buying used parts there are some buttmunches out there, if possible have a knowledgeable person check them out as soon as possible if not at point of sale(POS).

When you get to the point car is not your 100% daily driver and you can make supporting changes. Then think your plan, for now mild mods. a year or so from now maybe something different.

Novaette 12-22-2017 04:12 PM


Originally Posted by Kevova (Post 1596233230)
Because of your application oval track, 113 l98, 175-195 cc heads should work. You don't want ports or lift that is too much where torque is lost. The stamped steel long slots 1.65 did a pretty good job for decades before rollers came down in price. There is a benefit to rollers, they reduce friction and wear. They also require additional attention when installing so that roller tip is centered on valve tip, if not bad things can happen. I would be careful buying used parts there are some buttmunches out there, if possible have a knowledgeable person check them out as soon as possible if not at point of sale(POS).

When you get to the point car is not your 100% daily driver and you can make supporting changes. Then think your plan, for now mild mods. a year or so from now maybe something different.

Thanks! Lotta good info. I do have a vortec 350 in my Tahoe that I may use the heads, if they are good, but don't know if rebuilding them is worth it against buying new. Once I get the the point of no longer a daily driver (if ever, I just love driving the car) it will be a roller 383. You guys here are great. I need to get more corvette parts on my car!

cv67 07-13-2018 02:54 PM

Youll never see a real gain going to roller rockers with that type of cam, the stockers are just fine.
x2 that cam in your eng is almost identical to the l82 I wouldnt seek out another cam that old.
With that gear and budget? Maybe a set of Promaxx heads, Isky 264 mega cam should pick up nicely.
If you use vortec heads you gotta use the intake, too. You can buy them from GMPP or Summit with the upgrades


All times are GMT -4. The time now is 10:53 AM.


© 2024 MH Sub I, LLC dba Internet Brands