Firebreather

I'm having some timing and a/f ratio issues with my car (https://www.thirdgen.org/forums/tech...day-found.html) but I'm working things out little by little and wanted to see how much hp are this engines capable of with the factory 083 heads in place.
I still have hp gain opportunities in things like larger headers, hotter cam, some internal modifications, PCM tuning etc. but I kind of believe that something close to 400hp at the flywheel might be capable with 083 untouched heads. Please post your mods and dyno #s to have an idea of where I am at and what kind of numbers are possible. I'll go first:

350 L98 with afpr, 24# inj, Superram, 52mm tb, 1 1/2 hooker lt, 3" exaust with flowmaster, no smog parts, hypertech chip, underdrive pullies, compucam 2032 (214/220 112), 1.6 roller rockers, stock unported 083 heads.

279rwhp/307rwtq (just 28-30 degrees of total advance and 11.7 a/f ratio - see thread mentioned above)

With 20% loss that becomes 349hp/384lbtq at the flywheel with all sorts of tuning issues.

With headers, tune and cam I believe that I could find maybe an additional 30hp to the flywheel. Anyone with numbers??

Firebreather

I guess no one even bothers to visit the dyno if the 083s are still there. Hehe

Orr89RocZ

iTrader: (20)

I made 254 with just bolt ons and lean tune. Likely had 260-270 in it with fuel. Not many cam the stock heads because the lift limit on them. Without machining they are generaly limited to .470-480 depending on your measurements and not many roller cams are made for that. With offset lock/shim mod you can get .510-.520 maybe. Beehives may give you similar since they have thinner retainers i believe. Also some guys shave down their retainers to gain clearance. Alex's Parts company sells a spring kit that should get you .550". Guy on drag boards runs it on a .540 cam in stock vortecs with no issue and ran high 11's.

I think 083's can support 375 hp which is near 300 whp. I dont think you will get more than that. Flow is low on the heads and the port starts to go turbulent above .500". Mild cleanup will greatly help. I guess general theory would say approx 2 hp per cfm so a head flowing 190-200 cfm would make 380-400 but that would be a perfect world setup which most setups are not

Your numbers are pretty good. Maybe 10-20 hp left in it with cam changes and maybe abit more header tube diameter but again it approaches 300 whp which is a good bit from those heads. Aluminum L98's should be good for 320 whp or so but they have abit more flow. Not much but abit more helps. If the heads would support much more than 300 it would take a crazy cam lobe like a superstock type grind to hold valve open long and slam it open and closed. Not very streetable

Firebreather

Thanks for the reply. I already bought 1 5/8" headers so i hope that those, along with a proper tune, should help me pick some aditional 15rwhp maybe.

Orr89RocZ

iTrader: (20)

Yeah it should come around with abit less fuel and perhaps playing with timing curve. Other than that it should be approaching its limits with that cam

Damon

I'd work on the tune and leave the cam out of the equation for now. It's not just the peak numbers that a good tune can affect it's all the part throttle/transition stuff that can make the car much more responsive on the street (but rarely gets addressed just tuning WOT on the dyno).

When you're ready to step up the game, do the heads and cam at the same time. No point trying to find the optimum cam with those heads when you could start with a radically better set of aftermarket heads and then optimize the cam to them instead of trying to work within the limits of the mediocre -083s. And, of course, tune, tune, tune, AGAIN.

I think I can tell from your post that you are the kind of person who is capable of devoting some time and attention to the details. If I'm right, you should consider doing your own tuning (with some help from the locals here who can bring you up to competence on how to do that rather quickly- we have a board devoted to doing just that). At first, you will get worse results than just paying somebody, but you'll quickly move up the learning curve and graduate from just hitting good WOT numbers to putting some serious "snap" in the tune at all RPMs and throttle positions. HINT: An aftermarket stand-alone wideband makes just about any hack a tuning genius very quickly!

Perhaps a little daunting at first, but you won't be scared off by making more significant changes to the engine later since you'll have the confidence that you can tune it successfully yourself, knowing you can pull the most out of whatever combination you want to try. Then your friends will want you to tune their heap of parts for them......

Fast355

iTrader: (2)

That cam duration wise seems smaller than the Comp 268 cam. I know a junkyard 350 was run with the 083 TPI heads and 268 XE comp cam. With an edelbrock intake and Q-jet they dyno'd around 320 HP at the flywheel.