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ok, my motor is finally built, pump's freshened up and reinstalled into the boat, motor goes in this sat. and now its time to get busy on my carbs.
here's what i got, i need jetting recommendations and an idea of gph required to run this combo 6500rpms(b-cut dominator).i've already did the little cut-out and pluging to convert them to boost referenced.
475 bbc 4-bolt
eagle 4340 forged crank(fully balanced rotating assembly)
eagle h-beams with l19 bolts
protopline 320cc alum heads with 2.25 and 1.88(no port work done to heads)
crane gold 1.7 rollers
comp blower solid roller with 652 lift, 255 262 duration, 114 sep at 110 centerline
9 to 1 compression(srp blower flat tops)
bassett short twisties
weiand 6-71 blower(it made 8psi on a 525bbc? at 15% over)
dual holley 4150 750's boost referenced
msd btm ignition system,msd dist,msd blaster 2
anybody got recommends for jetting and what pump size its gonna take to feed em? i started a thread a months back about this but its gone:eek:i'm runnin a 02 system for fine tuning but i'd like a good solid place to start with the jetting and fuel needs. thanx, tom e.
p.s. i've got a new holley black pump rated at 140gph, will this be enough to maintain decent pressure??
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Try stock jetting, you will be pulling fuel thru the carb better then na, do a plug check on just the primarys, then jet if needed and then do a plug check for wot.
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i would check holleys website. they sell 750 dp blower carbs. i know they are boost referenced and you can check the complete specs for them. mike
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I run twin 750 DP's on my 509 with a 420 B&M blower. Best power on the dyno was using 74's on the primary and 78's on the secondary. (878 HP) I run a Holley blue pump set up with a return style regulator.
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this is from the holley website. #80576 contoured main body
jets 76p with 10.5 pv 87s no rear pv 31 squirters front and rear
boost referenced also also states for dual 4 barrell and 6-71 8-71
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this is from the holley website. #80576 contoured main body
jets 76p with 10.5 pv 87s no rear pv 31 squirters front and rear
boost referenced also also states for dual 4 barrell and 6-71 8-71
That's sounds about what i used on the 750's. I wouldn't start with anything less. I think I used the 50 squirters, though. Start big, bring extra sets of plugs!, and work your way down. Keep you timing conserative until you're consistently showing color on the plugs at high r's. Getting that balance is like riding a razor blade. Caution is the order of the day.
After you've got that dialed in, go have fun but keep an eye on the the plug readings after you have been running at high r's, and save your lunch money for some dominators!
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That's sounds about what i used on the 750's. I wouldn't start with anything less. I think I used the 50 squirters, though. Start big, bring extra sets of plugs!, and work your way down. Keep you timing conserative until you're consistently showing color on the plugs at high r's. Getting that balance is like riding a razor blade. Caution is the order of the day.
After you've got that dialed in, go have fun but keep an eye on the the plug readings after you have been running at high r's, and save your lunch money for some dominators!
i want some dominators, but i'm gonna save for a good 8-71 for next season;) maybe i can swing some rebuildable dominators and sell all my set-up.
do you guys think the above specs are for a carb that gets reference from the meter plate port? 10.5 p/valve sounds high, i keep getting everyone telling me to run 2.5 in the frt. and plug the rear as mentioned. is there any difference in powervalves between the factory 750 blower carb and the modified 4150 750's? i've gotta run a boost line up to my carbs for reference thru the spark advance ports, thru the modified throttle plate, up to my frt. power valve port.
i appreciate the help fellas. i can't afford to lean this thing out and melt down, it'll end my summer fo sho!:eek:
