338 gpx mod

[338gpx]

What should a reasonable hp range be for a 338 mod.
I'm running a 75 338 xb cylinders.
I would like to know what hp i would need to be competitive
in vintage drag racing?
thanks
What should i do to the motor. clutch etc.
I started to mod a 75 338 gpx with xb cyl.I want to run in the vintage drag racing in canada what would be good numbers for hp for me to be competetive.
here are the numbers that i have already
66.41 hp with 39.14 ft/lbs at 8912 rpm any information would be great

I'm running 36mm mikuni's and a 79 srx/exciter secondary i have a 78 exciter clutch and a 102 comet. I am running the stock 75 338 pipe shorted 1.5 inches the exhaust port bhas been raised and the tranfer ports cleaned up. Thanks

 

[RJH]

QUOTE: for me to be competetive. QUOTE

A thunder jet with your engine.

No matter what - the best working GPX will not beat the beat best working TJ in a drag race.

On the other hand;
The best working GPX against the best working TJ will win on a half mile ice oval, but it takes about 3 laps to catch the little things.

Good luck

 

[thunderjet440]

I think your in the ballpark horsepower wise,the only other 338's i heard being dyno'ed made 69hp and 73hp-with a modified gyt kit.
Have you had your combustion chambers modified according to the gyt manual? thats supposed to be good for 3 to 4 hp right there-from what i told

 

[338gpx]

No i haven't done this i'll have to find a good machinist to do this. I was wondering if i cut the baffle off the stock pipe and just use the stinger if that would help. thanks

 

[thunderjet440]

well it would sound cooler!
I'm not sure what the stinger length would have to be though.