I've been doing a ton of research for a heads/cam package for my '96 LT4 6-speed. My car has 4.11s in the rear. I'm getting longtube headers installed soon and deleting the cats. My car is no longer required to get emissions-tested.

95% of my driving is on the street, the other 5% an occasional trip to the track or drag strip. With that in mind, my goals are:

-Good reliability, first and foremost. I want to drive the car, not spend a ton of time repairing/replacing broken valvetrain parts or troubleshooting issues. I'm more than willing to give up chasing those last few peak HP in exchange for bulletproof reliability.

-Good drivability/street manners. I don't want it to be a PITA to drive in stop-and-go traffic, or have low vacuum problems.

-A broad powerband with strong midrange power, and good throttle response. Ideally, I'm shooting for around ~380-400 RWHP, but again I'm not chasing a dyno number at the expense of reliability. If the final number is a bit lower, so be it.

-I'm targeting a 11:1 static compression ratio on 93 octane pump gas. I've been playing around with DCR calculators, but I'm not sure if the engine and cam specs I've been plugging in are 100% accurate.

I plan on having my factory intake manifold ported and port-matched to the cylinder heads, and upgrading to a 58mm throttle body.

As far as heads go, I've narrowed it down to either:

AFR #1032 Eliminator CNC 195cc "LT1 Street" heads w/ 54cc combustion chambers
https://www.airflowresearch.com/195c...nder-head/p648

or

Send my LT4 heads to Lloyd Elliott or Advanced Induction for porting:
https://elliottsportworks.com/lt1-le2/
https://advancedinduction.com/LTX/AiLTx195ccLT4.php

I found some info from Lloyd himself about LE2 ported LT4s on another site:

"Ported LT4 heads will flow about 285/195 CFM reusing stock valves and keeping the runner volume about 205cc.

Larger 2.02/1.60 valves from Manley or Ferrea are shaped better than the stock LT4 valves and will add a couple of CFM (295/200 cfm)."


I'm not concerned with the cost difference between the AFR heads vs. ported factory heads. I want whatever's going to best achieve my goals.

I'm getting hung up on the camshaft selection. It seems like, given the air flow numbers my cylinder head choices are capable of, that a cam with intake duration somewhere between 224-228º and exhaust duration between 230-236º, lift in the .560-.580" range w/ 1.6 RRs, and a 112-114º LSA is the best choice. Plenty of off-the-shelf options within those specs, but I plan on having a custom cam made to optimize the setup.

I keep seeing recommendations to get a cam with "modern" lobe profile designs (faster/more aggressive ramp rates, etc.) for better power and response, but I've also seen that these newer cam lobes - Comp Cams' XFI, for example - are hard on valvetrain parts. Some have said that this isn't an issue as long as I get the right valvetrain parts. Another thing I've read is that with these more aggressive lobes, you don't necessarily need as much duration to get the same results.

Any help on this topic would be much appreciated.

 

What brand of longtubes are you going with?

 

Exotic Muscle 1-3/4" longtubes.

 

My 383 LT4 had AFR 195 heads,factory LT4 intake,1.6 RR, a comp 232/236 @ .050 on a 112* lobe sep,with 1 5/8 Stainless Works long tubes into a Corsa cat back with 6 speed and 4.10 gears. Made 441rwhp after tuning.

It was my daily driver at the time and was plenty street able but I did tire of the constant shifting. Went 1st/3rd.5th a lot. If you weren't going 80mph you didn't need 6th gear.

For a more streetable driving experience I could see a 228/232 cam on a 112* and it may be a little smoother but I wouldn't go any smaller or much larger. Bucking and surging from too large of a cam or a poor tune gets old quick.

I would go with a new set of heads hands down.I would still have them checked prior to running them.

 

Were your heads the 1032s, or the 1031s (65cc combustion chambers) or the 1039 LT4 "Competition" heads w/ 2.08/1.60 valves?

Also, what cam lobes did you go with, and what was the accompanying valvetrain setup?

 

,I have a 93 LT1. I went with TPIS ported 180 AFR heads, ZZ9 cam, EM headers, 3.73 gears, 1.6 RR and a custom tune. My best run was 12.2 @ 115. It is a great package and very streetable.,

 

This was all done 15+ years ago so all I can tell you is they were LT4 port and I don't recall them having 2.08 valves but not sure. Whatever they offered in the 2010 time range. Had the guy who built and install it pick the cam lobes and they were comp but again with that old of a timeline I couldn't tell you. Rockers were the factory 1.6 rollers that came on LT4 motors which were made by Crane I believe.

More advanced cam lobes now I am sure but the most aggressive lobes don't always mean the best for longevity of valve springs.

 

I went with an LE2 package with ported LT1 heads/intake back around 2006, has been great. His cam back then was a 230/230 106 LSA, sounds great with my exhaust, did 402/360 rear wheel when I had it tuned. Just go with what Lloyd recommends or Adv Ind., whomever you go with. I would get the Comp Eliminators (maybe the 210's especially if you think you will do a stroker later) and have those shipped to him and send your intake for port matching, then sell your LT4 heads. My LT1 heads did 280CFM.