Q: I have a Chevy Caprice with a 350 4-bolt main, a 292 Lunati cam with .480” of lift, and a high-rise intake with a 750 Holley carb. My heads have been worked with 2.02” intake/1.50” exhaust valves, a spring set for .480” lift, ported heads, and headers.
I also have a 350 transmission, fully rebuilt with a stage 2 shift kit, 2,500 rpm stall, and an 8.5” 10-bolt rear end with limited slip and 3.73 gears.
At the strip, my car has a very slow start, but when it downtrack, it’s pretty fast. What do I need for a quicker break?
By the way, do you think a 350 Chevy engine can compare to a 400? Would it be better to convert the 350 to a 383?
A: Sounds like a good ride!
We have a few tweaks to suggest. That 750 carb may be too big if your compression is under 10:1 or so (though it would pick up on the top end). A single-plane intake would also take away from the low end. Changing parts could help, but it would be a trade-off.
Check your fuel pressure at takeoff to make sure you’re not running lean. And check your timing. You might also try advancing your cam 4 degrees to help your low end.
Converting a 350 to a 383 will make more power, but the conversion alone is not worth the cost. Dollar for dollar, there is more power to be had from a set of aftermarket cylinder heads than from porting the stock set or a 383 conversion.
In a heavy car a 292 advertised duration cam is too big. Go to a 3000 stall 10” converter, even though your cam specs say 2500. Change to a MSD distributor which you can tune the timing advance curve far easier than a HEI, using the different advance limiter bushings. Use one light silver spring and 1 blue spring. Put the large black 18 degree bushing in. Set your initial timing at 18 degrees, which should then give you 36 total. And connect the vacuum advance to full manifold vacuum.
just change the advance curve springs to let the timing in sooner this should make it more responsive at lower rpm if you are using the stock springs the advance wont come in until 3500-4500 rpm its according to were you buy the curve kit I bought mine at summit racing for under 10 bucks it has a chart for what dose what you can also mix and match for more tailored curve.this is a advice from dave fieburger at hot rod.my Camaro did the same thing and this fixed it.