I have an early 86 coupe with iron heads. I want to change the cam. I have roller rockers 1.6, 1.5 installed. I wanted to know what cam will work with a stock bottom end? I plan on changing the heads in the future, for right now the heads are staying. The car is for the street, light to light. I just don't want to change the cam again.

Also, do you have to remove the radiator to change the cam?

thanks.

 

LT4 hot cam

 

You have to remove the radiator and condenser to replace the cam. I was able to move the condenser out of the way without disconnecting the A/C lines. This is a huge job to do. The longest part of this job is removing and installing the intake manifold. I recommend finding buying a Miniram or LT1 converted intake for easy removal.

It is very important to know what RPM range you want your power to be in when selecting your engine mods. Because all the components have to work together. If you have good parts but they are not in the same RPM range, then you get stuck with a dog.

First off, choose your intake manifold style. TPI is low RPM, Super Ram is mid RPM, Miniram is higher RPM. Usually most people spin their engines to 6000-6500 RPMs with a Miniram, so it's not too crazy of a manifold.

Secondly, choose your cylinder heads. A 180 or 185 cc head will be good for a TPI, a 180, 185, or 190 cc head will be good for a Super Ram intake, and 190, 195, or 200 cc head will be good for a Miniram. Cylinder heads and cams are not the place to cheap out on when building a motor.

Thirdly, choose your cam. Contact Comp Cams or any cam manufacturer for a cam recommendation for your selected combination. You can install the cam before all of the other things, just make sure it will compliment your intake and heads when they are installed later on. By the way, you have a flat tappet cam in your engine. You cannot buy a regular roller cam for it. If you want to go to a roller cam, you will need a retrofit roller cam kit.

Thirdly, choosing your headers. A 1 5/8" primary long tube header will work good for a TPI, a 1 3/4" will work good for a Super Ram or Miniram. Don't waste your time with shorty headers. They don't do much for these engines.

Fourthly, choosing your exhaust system. Most people end up going with a true dual exhaust system, that is what I recommend that you do as well. A 2" or 2 1/4" exhaust system will work great for a TPI or Super Ram, and a 2 1/4" or 2 1/2" will work good for a Miniram. By the way, I didn't notice any difference on my Miniram setup by switching from a 2 1/4" to 2 1/2" exhaust.

Lastly, your gear ratios. A 3.07, 3.23, or 3.33(MAX), would be good for a TPI. A 3.07, 3.23, 3.33, 3.45, or 3.54 will work good for a Super Ram. And a 3.23, 3.33, 3.45, 3.54, or 3.73 will work good for a Miniram. You can use different gears if you want, but those are what I would recommend.

Remember, these are just my opinions and others' opinions may vary. The point is, everything has to work together.

 

Basically everything in front of the engine will have to come out to get the cam out of there without lifting the engine out.

You will have to decide whether you want to keep it hyd. flat tappet, or make a roller cam conversion. Roller has a few more options, and generates less friction than a similar tappet cam, so a touch more power. You will need a custom tuned chip for a cam change.

But the important questions are what power level you want, what intake choice you want to go with, and your budget.

 

Ok, i found your stock cam #14094728 and its a flat tappet 202/206 @ 0.050" and 0.403"/0.415" lift on 115 lobe separation angle. The TPI induction likes a wide LSA and i would go no tighter than 114 LSA. Comp cams has a turbo cam that i think makes a good match: Xtreme Turbo XT262H #12-253-4. Crane has a grind #2040, part #114132 that looks good or Cranes H-266-2 #113931 or last the Z-262-2 #113511.
But i think i like this Crower cam the most: part #00230.

Good night.

 

You can't simply change a cam without matching stuff. What is the intake, heads, headers and ECM program going to think of it all? Even if they do limp along without ECM tuning, you are not going to get much more than what you have without the tuning. Either waste money or wait till it breaks then get a motor that is set up right from the get go. This is like buying bits and pieces of a suit from all over and trying to look good. What you end up with is a clown suit. That or get a suit that is made so that the pieces complement each other.

 

6500 on that old a stock bottom end would scare me.

IDK. A true dual setup isn't going to be something you can do out of the box. I would imagine it takes some pipe cutting. What would the point be though? What could a true dual really achieve over a large 3 in single that is mandrel bent to fit? Install would be way simpler with a kit, wouldn't it?

I'm also sure he would have to have the ECM tuned via datalongs or dyno or it probably wouldn't run right. It was drivable when I put intake manifolds and Tri-Y headers and an exhaust system. Drivable, not good driving till John Lingenfelter tuned the ECM.

 

I've read on this very forum many times of people who spin 6500 RPMs on stock bottom ends. In fact I even know a person who does on an L98 bottom end. Me personally, I only go to 6000 RPMs with mine but I have never had a problem.

Well of course, you'll always have to modify things when you do modifications... hence the term modifications. Reason why I mention it is because it seems to me like aftermarket true dual exhaust systems are more common than Y-pipe systems on these cars.

 

Thanks for all the information. I am looking to gain a some more power for the street. I am not looking for a screaming drag car. I have TPIS LT headers with a true dual exhaust and a 3.54 rear. I have a TPIS big mouth intake. I would like to change the heads in the future. What I am looking for is a cam that will work with my bottom end and the few bolt ons. I did install roller rockers with new springs.

thanks again

 

If you intend to stick with the TPI style, you need to change the runners to AS&M, port match the plenum, and make a decision on your head choice before you go changing the cam. Even if you want to do heads later, make the choice now, so you can match the right combination up later.

I would look more towards the ZZ9 or Accel 211, or something with similar specs @050". Anything bigger than 215-220 on the intake side would probably be wasted on a 350 TPI engine. If you then picked a head in the 170-185cc range you should end up in the mid 300s powerwise.

You will need the chip done after the cam change, then you will want it retuned after the heads go on it.

 

That's all I am looking for. Is the LT-4 hot cam worth looking at?

 

I would not go with the Hotcam, it will want to rev more than the TPI will let it. Go just under that.

 

when you telephone a cam maker, double check. I called Comp cams once and was given a cam for the 87 and later engine..thats the roller cam engines. Mine is an 86, NOT a roller motor. Had to call the back days later and still gonna call again this winter. Oh , I never go over 5,000 and don't want to, its a street car. The cams I look at usually top out at around 5,0 to 5,2 or 3/.

 

We share the same iron head motor, so I can give you a great recommendation with first hand experience.

CompCams #12-238-2 XE262H-10
Lift Int 462 Exh 469
Duration Int 262 Exh 270
Dur @ .050 Int 218 Exh 224
LS 110.0

You will need to pull the radiator and A/C condenser and drop the pan to properly install the cam cover.
I bought the cam, timing gear & chain, 1:6 roller tip rockers, springs and keepers all from CC.
It required a tune to run properly. I get 18-22 MPG on regular fuel. (Premium nets zero performance advantages)
However no modifications to the OEM valve covers or spring seats were required and I used the factory pushrods.
Running the Bosch (pink) injectors at factory pressures.
It idles with a growl (old school small block sound) and has great power response with factory heads and stock TPI tubes and plenum.
I have better than 20K on the motor now (stock bottom) with a kali smog cert that passed with flying colors.
I suggest MrWillys to help you tune it. He's still supporting early ECM's for C4's

Best mod I have done for my C4 It sounds and runs hard like a Corvette now!!








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Thanks again for the information. I guess it would be a good time to change the water pump and timing chain. I know I need a tune. Who is Mr ******?

 

I didn't have any issue going with aftermarket. I got a set of TPIS headers that went all the way back to the cat, bought a Random Tech cat after I found out the noise a hollowed out cat makes and a Borla Stinger 3 in exhaust. All parts fit together.

How does a true dual work? Won't it eat up ground clearence and you have to cut and paste it to make it work? My Borla and several "post cat" systems just bolt on. Get a cheap cat if you want for the car and headers with Y pipes. Hookers are cheap but you get what you paid for. My TPIS allows me to get to plugs without having to go under the car or take the starter out. Pretty fast job.

A plus is that although people will say "I am not building a race car (I want to cheap out and get good stuff)" it will allow for future expansion instead of buying barely adequate today and having to buy the right stuff tomorrow. I bought barely adequate heads today and tomorrow, had to throw away a perfectly good LPE short block. Great savings.

 

With the systems that I've used, they all bolt up directly to stock manifolds. If you want to use them with headers and you have to cut them and weld the flange pieces. Also, I have Hooker long tube 1 3/4" headers and I can change spark plugs on my engine in 15 minutes.

 

A CF member here. DO a search on his name, MrWillys. Not sure if I have any info laying around to share.

 

Congrats! I always believed that you start with the cam and work outward from there.

 

I guess. That was not my experience in my F-body. They were hard to get in and were not really good quality and were a royal pain to get to the plugs. I know I needed new headers after my Tri-Y got damaged and IIRC, I got a super deal on them and spent a lot of time trying to get the passenger side to go in properly. Many beers and a lot of swear words later, it finally slipped in.

Do the brackets all fit on your Hooker headers? Some have reported that the AC bracket supports don't?