hi everyone, thought you might be interested in 1/4 mile times with new 383 mods. the motor got bumped up from a 218 duration 458 lift cam to a 224/230 duration 510 lift cam(with 1.6's). i also swapped the holley 650DP for a 750DP. the rest of the setup is performer intake, ported stock 350 heads, 1 5/8 hedders, 2.5 inch exhaust, carter 6psi fuel pump, msd.

best time was 13.7 at 102 on stock rear with 3.23's and open rear.
60 ft was 2.1


Brian

 

You should be getter better times than that. First...get a posi!! That will put you in the mid 13's easy. With a 383 you should be running the 1 3/4" headers, and a 3" exhaust system (high flow cat and catback or just a good 3" cat back system with straight pipe for the cat). The ported stock 350 heads are probably killing you and probably still are not flowing as good as a set of aftermarket heads, unless some serious porting and larger valves were installed. Those stock valve sizes don't get it on a larger engine like the 383. I would go with some Vortecs or if you can afford it go with a set of AFR Heads. I bet you'll be in the low 13's then. What's your timing set at? Might want to bump it up slightly to around 8-10 degrees if it isn't already.

It does sound like your choking your motor with the exhaust and heads and they aren't matched to the size cam you are using.


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1988 TA 300+hp 350 w/ TBI and Holley TB unit,
WC T-5, 3.42 gears w/ Auburn posi. MSD 6A, edelbrock TES headers, dynomax 3" cat and cat-back system, ACCEL coil, polyurethane bushings all around, aluminum driveshaft, Mr. Gasket open air cleaner.

1993 S-10 w/ 4.3L V6 TBI, slightly bigger cam, Mild polish job and 3 angle valve job on heads, Edlebrock TES headers, Dynomax cat back, MSD 6A, ADS chip
(bought from my dad)

2000 GMC Sierra Regular Cab Stepside
285hp 5.3L w/ 3.42 gears and locking diff. (sold to my dad..no!!)

 

Those times seem kinda slow for a 383. My friends vortech crate motor with 1 5/8 headers, suspension mods, tires, and a 750dp ran 13.50s with a turbo 350 trans. He also had an msd ignition and a holly fuel pump set a 8psi

 

i know that the intake and exhaust are really hurting me. i have a exhaust cut out in the garage waiting to go on(for racing) and i think that i decided on the weiland stealth for my new intake. i am allways wondering how much these heads are hurting me. i bought them from a local motor shop who told me that they had 202/160 valves and were completely ported by jasper engines. how much material is usually taken out on a port job? i think that stock runners have 150 runners, so does a ported set have 160?

Brian

 

It really depends. If they did a major port or a minor cleanup. With a good set of aftermarket heads, in the 190cc-200cc runner range, it should really open the mouth on that motor.I got the Sportsman II's, but if I had the money, I would do the AFR's.

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,Hypereutectic pistons,9.8:1 compression,HPC Coated RPM intake, Speed Demon 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, K-Motion springs, Comp Cam 1.6 roller rockers, Lunati adv.292/230@.050 with .512 lift,Crane pushrods,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with B&M 3000 stall, Powertrax NoSlip Locker, 4.11 gears.