PGSS you asked me if I could post numbers on a different thread so i wanted to start a new thread. last one I did was a mild driver 401. used longer rods and stroked crank. so 3.69 stroke over stock 3.64 stroke. .021 over bore came out to 413 cubic inches. mild 218-224 solid lifter cam on a 109 LSA. first cam was a 224-230 solid on a 111 LSA which i didn't like the bottom end power and replaced it.with the smaller cam it made 355 hp @ 4400 rpms and 458 tq @3500 rpms.
the first nailhead build was a 425 stock stroke and bored .038 = 432 cubic inches. 218-230 hyd cam on a 110 LSA made 400.6 hp @4650 rpms and 505 tq @ 3550 rpms. track time was 12.89 best ET with 3.23 gears and a 2-speed switch pitch tranny
My 401 will run 99 mph in the qtr mile, and weighs 3950. It is a HEALTHY stock build, with Toms pistons and a tiny 212/218 cam. that transelates to 280 at the wheels, 350 at the crank and most calculators are in agreement with this number (Moroso, Wallace Racing, etc..)
on my middle build 425 longer rods and stroked to 3.75 from the stock 3.64 and bored .038 = 446 cubic inch. 230-235 solid lifter cam on a 109 LSA. made at the crank 427 hp @ 4500 rpms and 549 tq @ 3500 rpms. ran 12.38 again with 3.23 gears and the 2-speed in the same car as the 425. after that I put a 235-240 on a 109 LSA solid cam and a little more head work and made some small but noticeable changes and could feel the extra power but never went back to dyno or track. car weighed with me in it was 3875 lbs
Well into the 400's for HP. for a Nailhead just wow. They sure do put out close to the rated TQ and you really made them into TQ monsters. This thread is a treat!
a side note on the 401 when i took the heads to get some port work done the porter said they were already ported. i think they were just hogged out because bottom end always felt a little soft but did pull good in the upper rpms . the engine was rebuilt when i got it with a stock bore and ta- rv 12 cam 205-215 duration. it had 50 miles on it when i bought the car i put less than 200 more miles on it and pulled and rebuilt the engine it was a dog even with that small 205-215 cam it had no bottom end at all and no power in any rpm range when i got it.
it's hard to get high hp numbers with the small valves and low flowing heads because you can't make power in the upper rpms but easy to make big torque numbers down low.
guys don't forget most 1/4 mile times back in the day for the 65-66 gs was low 15 seconds one i seen was in the 16s
The one in the 16's was a 65 with AC and a 3:36 peg leg. Didn't have a chance. It's kinda a shame that they did 1/4 mile tests. I think a 1000 ft. test would be a better comparison test. I use to have my complete stock 66 GS at just about 900 to 1000 rpms while in Drive easily cruise up the steepest hill in my city with 5 kids in it. Once you climbed this street you could see out over 300 miles! This was even when it hit 100,000 miles and it had a 3;23 posi. Drove it daily for 8 or 9 years and only till the day I sold it I found out all that time I only had a Carter AFB 500 on it that the original owner had put on it. I think I posted this 5 times before. Still fell flat at around 4400 like the original 625 cfm would of i'm guessing though but had wicked fun on a cold day.
the 401 was about 9.25 I wanted at least 9.5 but things got mess up . the 425 was 9.75-9.8 and the 446 was 10.2-10.3, 9.65-9.75 is what I would shoot for if I was to do another one.
Are running bigger than 1 5/8 " tube headers? I know Rhett has manifolds but I believe match ported some?
