sorry if this has already been asked but Im having trouble finding good info on proper carb selection for my 351w. the plan is to do nothing more than install new bearings, gap the rings and use all ARP hardware on my 94' F4TE 351w roller with stock cam(f303 in the future?) and GT40P heads. so would a 750 be a little excessive for such a mild build? less is more right? i want to make sure it has good throttle response with decent low end torque and can get me close to 800 RWHP with a 70mm ON3 single turbo kit. does this sound reasonable? maybe a 650 would be better? thanks in advance to anyone who can help, i will be purchasing a second hand carb and rebuilding it hangar18 style

 

id go with a 650 cfm,, i don't think your going to see 800hp though with that turbo

 

I have a 650DP with the appropriate mods ready for my car. My setup is very similar to yours, 351 that is stock for now have some GT40's that will make their way onto it with a decent flat tappet cam after I get the proof of concept built and running. My turbo is a bit larger on the exhaust side but compressor side is about the same. I picked the 650 because with 351 cubes, the signal should be great and that should help the carb do it's job better. When I get to the point of running and tuning it, I'll be posting here for advice and such. Good Luck with your build.

 

650 it is, is there any particular benefit to a double pumper? what about mechanical vs vacuum secondaries?

 

well dam, how big would i have to go for 800hp? 76mm? 80?

 

would prob need a more compressor as you stated,, but if you have a p trim turbine, that will be the limiting factor ,,, if it is a ptrim you will want to run a big gate to bypass the extra exhaust

as a rule of thumb you want the compressor inducer and the turbine exducer to be about the same size on a turbo

 

I was thinking his biggest limiting factor was going to be the P-trim exhaust on that ON3 70mm turbo. I have a Garrett TV7511 that is T6 flanged (I'm not sure of the turbine wheel specs other than big) and has a 71mm inducer on the compressor wheel. I realize the comp wheel isn't all that big, but was under the impression that it would be able to get me into the 800-850 range on a 351 based motor. Is that a pipe dream? Thanks.

Greenfox,

The carb sections here don't get a ton of traffic these days but they are loaded with great carb tech. And there are still several people here that have extensive blowthrough carb knowledge who are happy to help where they can. What I'm trying to say is that you have some basic questions that have some very complicated answers, if you spend some time reading threads by Brent, rotoryota, BlownShovel, CW25, Rickracer, blown385, brianj5600, brianj5600, Tuner and SWT Racing just to name a few you will probably answer many of the current questions. These are not the only good blowthrough guys here by any stretch, just a few users off the top of my head who have posted a lot of good info here through the years.

 

you will see guys getting 6-650 with ls engines running the gt45 (iirc has a 69mm comp inducer and a 77/88mm turb wheel)

not saying its totally impossible

 

my understanding is that 14psi boost would theoretically double the power since youre doubling atmospheric pressure. if at stock im making 325 hp i would then need 14psi to get to 650 hp would i not be able to get say 20-22 psi out of a 70mm turbo? (crap this thread totally just went off on a tangent lol)

 

very nice, i wish i could afford it. this is just a budget build for me though hence the gt40 heads, cheapy ON3 performance kit, and second hand diy blow through carb. possibly in the future though, ive heard nothing but good things about C&S

 

x2 C&S always good!!!