i have a 302 with long tube headers connected to a flowmaster exhaust, electronic ignition, a holley 650 with spacer. How much power am I making and what would porting and milling down the heads do for the car power wise? Thanks!
That really depends on what year 302 you are talking about, the condition of the engine, state of tune, etc. Your carb may be a little big. I wouldn't go over 600 cfm on a 302. A small engine needs velocity (actually all engines) as much as, if not more than, volume for the sake of volume.
So let's look at your current setup. If it is a a pre emssions 302, then around 205-210 hp bone stock. Ifyou have full length headers, then add around 15 hp, add another 10 hp for duals (by the way I have NEVER seen a situation where flowmaster mufflers actually hurt power. Anyhow that is a whole other ball of wax). So right now around 230-240. Now add maybe 10-15 for your intake (if it is the high rise 1500-6500 rpm piece I am thinking of, probably even more if you were to upgrade your cam, or port your heads). So right now you are probably still at or around the 230-240 hp range. The reason? Well you are a tad over carbed, and you didn't mention if you have properly curved your distributor. Something around 10-14 degrees initial with around 38 degrees total advance (vacuum disconnected for curving a distributor) all in by around 2800-3000 rpm would get you a few more ponies as would jetting for your combo. Tuning could net you up to around 20-30 hp and get you an even broader power curve. So if you tune the carb and ignition you could be around 260-275 hp. Go with a mild cam (comp 268H, 256XE or 262 XE), and you would pretty much be around 300 hp at the flywheel. Port your heads and you would probably see another 15-30 hp. Ford did 271 HP out of a 289 with tiny little factory ports(the hipo heads only differed from non hipo heads in that they had screw in studs and guideplates), and shelby did 306 on those same heads, 350 with some porting. You could get even more with some RPM heads or AFR 165s.
I have a 289 in my '68 Cougar that is built with the following specs:9.66:1 compression, XE 256 cam, factory non hipo heads with studs and plates, performer intake with 1/2 divided wall spacer with 1/4" machined from the center, Pertonix Flamethrower 3 distributor, 1 5/8" Full length headers, with the distributor tuned for 38 degrees total advance by 2850 rpm and I did the jetting the old fashioned way, by reading plug color after wot. I can tell you that even in my relatively heavy car, it runs like stink with a 2200 rpm stall converter and 3.55 gears. Probably around 280 hp at best. But compared to the 205 it left the line with in '68? BIG difference.
