89BlueRSCamaro

Ok so can anyone post the information necessary for a cam upgrade....i have seen many post as to what works best for a 305 TBI, TPI, 350 and so on....well can anyone post the information such as the best cam and specs if someone is building a mild 305 or 350...and does it matter if its TPI or TBI, what kind of lift duration, LSA, and all the necesary equipment, lifters, springs, rockers, etc or if the stock parts will work...i am asking this because i do not know all this info and it seems that everyone always ask the same question over and over and it would be nice if someone has the knowledge to put the info together and make it into a sticky...at least as far as building a mild power street car....usually people that are building a street/drag car know this info...but not many beginners...like me.. well hopefully someone can do this...thanks...and asking because i have a 350 TPI and just wanted to change intake to ram air or something, cams and entire head rebuild since thats what usually happens when doing this, and custom exhaust...and gears of course (L98 i guess have 2.77 and i want .3.27 or something like this....nothing else. SSSOOOO......help

TKOPerformance

One major reason that this information isn't out there is that the cam is basically the brain of the engine. It determines it's operating characteristics and demeanor. Cam selection requires either substantial knowledge on your part, or you taking the advice givien to you by one of the cam companies. I know a lot about engines and how they work, and I usually get in the ballpark with the selection, but I still slways consult with the manufacturer to be sure that my train of though is correct.

In a street engine you want a wider LSA, because that will keep overlap down, even on a performance grind with more lift and/or duration. This will stabilize the idle and help with emissions.

A street cam typically has higher lift and less duration than an off-road cam, in part to combat the overlap issue mentioned above and still provide better breathing at realistic street engine speeds (6,000 or less max engine speed).

Engine size also determines how a cam will act. The same cam that is beastly in a 305 will be much less agressive in a 350, and may be downright sedate in a 383 or a 400.

If you don't have a factory roller cam engine, consider making the conversion with retrofit parts. A roller offers area under the curve that is much more important in a street engine than peak power numbers. A roller and a flat tappet that generate the same peak power numbers may be 20 lbs/ft in areas of the power curve below peak. The roller always makes more average torque, and that's what a street engine needs.

Shagwell

good answer, very informative.

89BlueRSCamaro

Very interesting...... .....so if for street i need a wider LSA and less duration than if you guys could help me out....how would this fit my engine then (Comp Cam 290HR12 230/244 @.050 .510/.540 lift with a Comp Cam 1.6 rocker 112LSA) ...as previously stated i have a 350 5.7L L98 and right now no real mods....just some 19# injectors...still need the APFR....and thats about it....sometime in Jan is when i will install dual exhuast with two new converters and some 2 1/2 I/O Dynomax Ultra Flow mufflers.....also what is flat tappet and guide plates and all that... i really dont have any clues as to what all this is...this year has been more hands on for me and learning since i started this Camaro project....i had never heard of this things....well thanks for the help so far guys....the more i know the more confused and fustrated i feel....but its all good....

1991CamaroRslow

iTrader: (3)

Rule of thumb for fuel injected cars is keep the LSA at or above 112, I've seen some of the LT1 and 4 guys get away with 110. on a TPI car you want the duratio at .50 to be at 220 or under. Most cars will benefit from a slightly smaller cam than you think, it's about matching them to your heads and intake. These are general guidelines but it will tell you where to start.

Shagwell

too much cam dude. - as stated, look for something around/under 220 duration. - Also, your motor should be a hydrualic roller cam. A flat tappet can easily be a loss in power/economy/throttle response. Flat tappet cams are non roller, i.e. hydraulic flat tappet/mechanical flat tappet. Roller cams are roller cams. Can be hydraulic or mechanical(solid) though. Unless someone has screwed you, a L98 car should be a hyd. roller. Look for 220ish @ .050 duration, 480ish lift. Good place to be for a street performance motor. The cam you mentioned would be REALLY big for stock heads w/o some fairly extensive mods.

TKOPerformance

Yes, too much cam for an otherwise stock engine, and too much cam for an engine breathing through a TPI. LT1s have much better RPM potential because the runners are about 3" long, whereas a TPI's runners are more like 12" long. The trade off is that the TPI is a low end torque monster and the the LT1 isn't.

Check out LPE or Crane, bot have a good selection of rollers. I have a smaller Crane cam than the one I'm using in my new stroker engine that would be good for your application in my 350. Part number 119621. The trick is that is isn't s stepped nose cam like an L98 would use stock, but this issue is easily skirted if you're interested send me a PM.

Abubaca

iTrader: (3)

I had all the same questions as you.

I mean this with the utmost respect...but...until you know what you're doing, wait.....buy a book....read....and come back and ask us to help you fill in the gaps. Once you're done, make the decision for yourself.

I had no idea what all that stuff was either, but I bought a few small block chevy books, read 'em cover to cover, then started asking questions. You'll have SOOOOOO much more appreciation and satisfaction when you've learned it yourself.

I don't remember who it was that said you shouldn't put anything on your car unless you can explain WHY you chose that part. Makes sense though, huh?

It's the whole give a man a fish and feed him for a day or teach him to fish and feed him for a lifetime thing.

GTA Sammy

iTrader: (1)

Hey 89..... You gotta read your stuff....
Check out ; 1)Small Block Chevy Performance by Dave Emanuel (HP Books)
2)John Lingenfelter on modifying small block chevy engines (HP Books)
3)Camaro & Firebird Performance Handbook by Peter C. Sessler (Motor International)
The culmination of these three books taught me alot! I'll skim through them whenever I get the chance. #1 & 2 are better in my opinion but # 3 may be a good place to start. Each gives you ideas on how to make more power and the reasoning behind why you don't do certian things like going with a huge cam, huge heads, huge headers.
This website has wicked information too...... Check out the Tech Articles and Faq's pages for more information........
Paul Huryk has a couple of good articles "Basic info everyone should Know" & "Gearing" , "Camshafts"
Tom Keliher wrote "Suggested Mods for 3rd Gen TPI's"
Hope that helps some .........
By the way I think that you should have 3.27"s in the rear anyway...... Check out the RPO codes (You'll find them in your console" while you're lookin around the Faq's and Articles

GTA Sammy

iTrader: (1)

Hey 89..... You gotta read your stuff....
Check out ; 1)Small Block Chevy Performance by Dave Emanuel (HP Books)
2)John Lingenfelter on modifying small block chevy engines (HP Books)
3)Camaro & Firebird Performance Handbook by Peter C. Sessler (Motor International)
The culmination of these three books taught me alot! I'll skim through them whenever I get the chance. #1 & 2 are better in my opinion but # 3 may be a good place to start. Each gives you ideas on how to make more power and the reasoning behind why you don't do certian things like going with a huge cam, huge heads, huge headers.
This website has wicked information too...... Check out the Tech Articles and Faq's pages for more information........
Paul Huryk has a couple of good articles "Basic info everyone should Know" & "Gearing" , "Camshafts"
Tom Keliher wrote "Suggested Mods for 3rd Gen TPI's"
Hope that helps some .........
By the way I think that you should have 3.27"s in the rear anyway...... Check out the RPO codes (You'll find them in your console" while you're lookin around the Faq's and Articles

89BlueRSCamaro

I read tom huryk's article and printed it out and have gone over it a couple of times....i was going to buy the thirdgen or camaro mod book that was on ebay Camaro Bolt-ON Performance by John Smith, and the Camaro Performance Handbook for 82-92 models by David Shelby.. they will get here by next week since i just ordered them yesterday....i really need to do my homework cuz i was just going to jump into this project just like this...but i am really starting to like this...knowledge is good....thanx for your input...and i will also look into what else this site has to offer.... i amazed at the info i have found...i am glad that there are people out there who take the time to write all of the tech articles to help out the beginners and those who already know who need a refresher...

TKOPerformance

Don't count out Smokey Yunicks Power Secret's either. It's geared a lot more towards long and short track racing engines, but what do you think the highway is? Seriously, he was light years ahead of his time and had more than just a hand in designing the small block that we all see today. He uses a lot of plain, and at times colorful languauge, and I found the book to be a great read as well as very informative. I had to read it about two times, and still skim through it and learn tons. Thanks for all the lessons Smokey, I hope the afterlife is free of tech inspectors that claim you're "cheating" again!

Lingenfelter's book is great too. Especially since all his knowledge is geared towards fast street cars. He's another one that broke the mold. Thanks to you John, you were taken before your time.

I also got a lot from the GM Perfromance Handbook that covers SBC, BBC, V6-90, and V6-60 engines. You have to bear with the fact that all of the parts info is presented with only GM parts, but there's still a lot of usable info there from the guys in GMs high performance engine program and some top NASCAR and other racing series guys.

Even now, I skim through the sections on what I'm working on to get a consensus about how to procede. There are great step by step sections in all of these books that deal with topics like degreeing a camshaft and checking valvetrain geometry. It's very hard to get that info from any other source.

Ashton89iroc

digging up an old thread, haha. You guys say you need to keep the duration of your cam under 220 for a pretty much stock 5.7 TPI? I'm in the market for a new cam as well. I'm rebuilding my 350, got a 3" exhaust from the header collectors all the way back, still considering if I should go .30 over or not, hypereutectic aluminum pistons, all new components for everything really. I got ahold of COMP cams and I picked out a cam, gave them my description of what I'm doing with the car down to every detail and they said that the cam I chose (part number: 08-464-8) would be a great cam for my engine and would function just fine with the stock rockers and all, this cam has at .50 intake 202 exhaust 212. The rep said I should see a .515 lift with the stock rockers.

does this sound like a pretty good cam to get or not?

abray1

Matching all your parts does the trick. When I first got my Iroc way way back when I was in college It was a low mileage 350 tpi iroc with 2.77 gears. I added a ZZ4 cam, tru roller timing chain, edelbrock headers, spiro pro wires and NGK spark plugs, a hypertech chip and 170 stat and lucas disc type injectors. That car would fly. The torque was almost like a big block. It wouldn't wind past about 4600RPM like all TPI cars but with the 2.77 gears it would out run LT1 cars. I was in college then and had the best time especially in the iroc. If I found a nice GTA or something still nice and was going to keep it stock I would do that same thing to it since all the parts are perfect for each other. The car got the same gas mileage or a little better (about 25 MPG) when driven right. You could bearly hear a lope at an idle but you had to be listening for it.

Tuned Performance

iTrader: (92)