I have an 85 coupe with a L98 350 and a 4+3 trans. The car runs strong but needs to be faster. Im thinking of a compleat rebuild. I would like some nice alluminum heads and a good cam to go with some more compresion like around 9:5:1. Are the edelbrock performer rpm heads good with the tpi? Any input on making my stock engine faster, with in reason, will be great :cheers:

 

Those are exactly the heads I'm running now. I bought them when I had a 355 CID engine in my 86.

Of course, now that I'm running a 415, I'd like to have a set of Edelbrock Victor Jr's.

All of the head flow tests I've seen show that Air Flow Research heads flow the best, but there is a downside.

Availability of those heads is a problem and, according to some posts I've read recently on this and other forums, their customer service leaves much to be desired.

Camshaft selection will be critical also. There are guys who have their favorites; some like the GM offerings, some Lingenfelter's. some Crane and others - like me - like CompCams. Opt for the most valve lift you can get; keep the Lobe Separation Angle on the wide side - 112* or more.

A wide LSA will give you a broader/flatter torque band as opposed to a cam ground on, say, 108* that will be more peaky. TPI engines prefer wider LSA's.

Duration choice is also a thing that will bring out differing views. For me, 224/230 @.050 would be the limit on a 350ish street engine if low end response and street manners are important. Even with the 415 I'm running, I chose to go with that duration since my car is a daily driver, not raced and street manners and power brake performance are very important to me.

More power can be made with longer duration cams, but as the duration goes up, down goes the low end/idle torque and the power peaks move higher in the RPM band.

Unless you opt for an improved intake setup, you won't get the results you're looking for in the higher RPM bands since the intake system becomes a severe restriction.

So when it comes to camshaft selection, 224/230 will meet your HP goals; how much higher in duration you can go depends on what you're willing to live with.

You'll need full length headers, a less restrictive exhaust system, re-burned PROM and mildly modded intake manifold, runners and plenum.

400 HP at the flywheel is do-able; getting that amount at the rear wheels calls for a bit more though.

Just my thoughts.

Jake




[Modified by JAKE, 4:19 PM 11/20/2003]

 

Pretty much any heads will take you to or near the 10:1 compression, unles you stay with the stock 72cc chamber size.

You will have to upgrade to a different intake system too, as the stock TPI setup won't get you 400hp with just heads/cam and bolt ons (at least I don't think so). The stock TPI setup runs out of breath after 4800rpms (some earlier). There are a LOT of options you can do and routes you can take. Search the forum for info on : Superram, Miniram, 219 Cam, Lingenfelter, Longtube Headers, Dana44, etc.. etc..

Good luck . :cheers:

 

Thanks on the info, I also planed to get a 58mill. TB, SLP intake runners and port the base. Sound good?

 

I went this route....



390hp & 445 ft/lb before tuning, dunno what it is now.
http://personal.tmlp.com/scorp/vette/upgrade.html

Everything you see there except for the nitrous and MSD components made those #s.

 

:D Ditto :

 

Very nice. Im looking into that tipe of intake system. Tanks

 

Whereabouts is Marston Mills? I've you've ever gone to New England Dragway you may of run into me or my friends before. :cheers:

 

I tried the 58 mm TB on my engine and ended up taking it off and putting the stock one back on until I could get a 52.

The 58 made throttle response so abrupt I found I couldn't modulate the throttle effectively in traffic. The car always seemed to be blasting away from stop signs/lights and in traffic even with very light throttle pressure.

It just flowed too much air too quickly for me to feel comfortable with it; I felt like "Speed Racer".

So I re-installed the stock 48 and, a few months later, got a BBK 52; that's the right one for my combination.

Engine Analyzer Pro shows my engine only pulls a max of 680 cfm anyway.

So I suggest, if you can, that before you go out and buy a 58, see if you can borrow both a 58 and a 52 from friends. Try them both and see which one works for you. Could save you hundreds of $$.

Hope this helps.

Jake

 

welcome to the boards!

listen to these guys! alot of these guys L98's hauls the mail :D

i'm basically doing what your doing to my 87 less new heads cause i already got aluminum (not the D ports but will serve the purpose for now). i'm just gonna get them reworked and punched. big mouth base intake, SLP runners, then port my plenum. with a ZZ 409 cam and 1.6 RR's.

i'm hoping to be around 380-400 hp and over 400 lbs of torque down here at sea level :crazy:

my best now with light bolt ons is 13.26 in my 87. no cam or head work done on a stock TPI, stock 1600 stall, stock tranny, and stock 2.59 rear gears on street tires :cheers:

you can look at my sig for my current mods and times.

some of these guys have ran 12.7x's with mild bolt ons with L98's :thumbs:

 

You're looking to do what Joe90 did. He's got his TPI 355 setup pulling 400hp. Pretty much 'looks' stock.
http://www.corvetteforum.net/c4/joe90/index.shtml

The SR like Scorp and Nuke has will also do the trick.

Cant go wrong with these proven results.

 

nice setup Joe! with that MPH you should be able to hit high 11's with a set of sticky BFG's :jester

BTW thats about what i'm trying to achieve. thanks for the info!

 

Here is a picture of the engine currently...black powder coated and just a little meaner...



Thanks....it is a real hoot to drive around :D

Actually, I think I'll get a set of these MT ET Streets http://www.superchargerhelp.com/show...&threadid=3329 They look really sticky...and are a proven performer.


[Modified by Joe90, 3:04 PM 11/21/2003]