1985 GT GT40P swap with cam and intake

[EarlyWormEatsTheBird]

Hey there y'all, I'm getting ready to swap some GT40P heads along with an edelbrock performer rpm intake, a trickflow stage 1 cam, and a holley 650 double pumper into my 85 with stock bottom end. What kind of 1/4 mile times and power figures should I be expecting with this setup? Also how much timing would be appropriate to run with this setup? This isnt a daily driver so I dont mind using 93 octane, nor is emissions a concern.

[bwguardian]

I have a similar setup on my 85 GT vert and I think that Holley 650 dp is too large, not to mention there are better choices. Also, no need to run 93 octane as I'm running 87 octane in mine with 15*-16* timing advance.

[Walking-Tall]

1/4-mile predictions... too many variables. Mentions a better carburetor choice for increased TQ & HP peaks AND across the board AVERAGES: a good ole Holley 750 double pumper or vacuum secondary. 300 horsepower shouldn't be a problem. At or a bit above 9:1 compression ratio, and with that camshaft, you shouldn't have any issue with 'er sipping on 87-octane and running 16-18 degrees BTDC for an initial timing setting, and 34-38 degrees BTDC total (initial plus centrifugal/mechanical (limited ("re-curved") to 10 distributor degrees, 20 crank degrees)) "all in" at about 6000rpm. Vacuum advance canister (another suggestion for a DuraSpark II distributor vacuum advance canister: one for a 1974 Ford F100 w/390 engine, is stamped with a "6" on it's stem, and so provides 12 crankshaft degrees) connected with full intake manifold vacuum. A similar combo here in my driveway works damn good. Good luck with it and have fun

[erratic50]

Way too many variables here to guess.......

without the limiting advance at the dizzy I would expect it would like somewhere near 12-14 of initial timing but you have to watch it. Actual advance varies a bit.

I agree with the thought of about 38 total. If you go too far you lose power and trash stuff.

Simply talking carb CFM by itself is not enough. There are so many factors in play like how its set, jet sizes, etc.

You don't have enough cam there to extract everything the combo is capable of. I've seen a car run in the low 11's and put 360HP out during a dyno session but it had a lot more cam and plenty of porting done on GT40's.

Stock vs stock most guys see a little more peak and midrange power from a GT40P head.

Lets say you get crazy on a hot cam and it want to breath and rev. The next issue is about 1 in 16 rod bolts is wimpy. Did you find an engine where they are all great or one bad one or two .... etc. Who knows. If you're going to spin it much past 6000 you may want to consider a bottom end refresh and going to ARP hardware for the rods.

My tired old 86GT has hung in there with my high RPM bounce it off the rev limiter antics but we've all seen them fly apart before too.

What do you want to use the car for primarily? That should dictate what you do.