73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: 305chevy c-10 on March 12, 2011, 10:20:39 am
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has anyone ran a 750 holley dbl pumper on a mild 355 engine .or will it be just to costly to drive ....with gas 3.55gallon ...ifso what about a 600 or 650 dbl
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I would run the 600.
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I'd have to agree,600-650 range for a mild 355 in a truck with a normal converter and mild gears.
Unless you would have like a 3000 RPM converter,and 4.11 ring and pinion,then a double pumper would be a good choice.
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maybe a 2500 stall and 3.42 rpm air gap intake ,vortec style heads
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Over 15 years ago, I ran a 750 double pumper on a mild small block. It ran horribly, truly a waste of time and energy. Everyone I knew even told me before I did it that I shouldn't do it. But, the carb was free, blah blah blah...yeah. It didn't work out well at all. I think I traded it to someone for a 600 or 650.
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x2 what everyone else said, too big
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I have a holley 600cfm with stock jets on my mild 350. runs perrrrrfect. You can always go with bigger jets and squirters. ;D
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750's are for big blocks. Period.
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750's are for big blocks. Period.
or smallblocks with forced induction!
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a nice 650 single pump vacuum secondary is the way to go for a mild street daily driver motor
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A 750 can be made to work, you just gotta spend some time tuning it. I ran a 750 on my smallblock for years. I had problems, but I think they were due to the carb having trash in it, me not knowing how to tune, and a big vacuume leak. I've even used a 850 doublepumper on my motor when it was a little more stockish. If you're lookin' for gas mileage, you're lookin' at the wrong carbs.
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ok i get it ......will go with 600-650 and electric fuel pump
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i made i mistake my carb is a 750 with dual feed lines ,not a dbl pumper if this makes a difference in if it would work in my 383 app .
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my carb is a 80508-1 holley daul feed elect choke /vac sec 750 .my question is has anyone ever put smaller jets in a 4160 carb like this.i think this route would be cheaper ( re-jet and rebuild it )verses buyin g a 650 carb for my 383 .i realy like the dual feed set up look .
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you can't get calibration kit for a holly that i know of.That is why i like carter or Edelbrock If you have your timing right and your spark advance is tuned right you can tune them pretty easy.
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so re-jetting this with smaller jets or squirtters won't work.i know i would get snappier throttle response from a small carb
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750's are for big blocks. Period.
LOL!!! sounds as if the 950HP wasn't be a good choice on my old 406. wheels up and 11s seemed to work out though. but in reality a 750DP is alot of carb on anything but a SERIOUS engine (think 375ish horsepower as a start).
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I don't know your engine specs but a 570 cm to 600 cfm should be all you need.
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*87-95 rollerblock 2 bolt main (studded mains )
*cam (roller) 268 @.490 lift
*procomp 1.5 roller rockers nonself align
*vortec EQ heads ,screw in studs withguide plates
*comp cams 7.2 push rods(5/16)hardened
* rpm air gap dual plane hi rise intake
*melling hv55 oil pump and pick up
*7 quart oil pan
*KB silverlite dished pistons .030
*procomp 5.7 rods with arp bolts
*3.75 eagle cast steel crank( 103523750)
*400 pioneer flexplate (fra-159)
*summit 400 balancer with removerable weight
*clevite rod and main bearings
*hasting rings
*liberty true dbl roller timing set
*pro comp hei distri
*procomp hi torque mini starter 3hp
*procomp 155gpm electric fuel pump and regulator
*350th trans b&m shift kit with 3.42 or 3.73 gears
* dual 40's flowmaster 2.25 exhaust with x pipe with summit long tube headers
*650cfm holley(80783c) or 750 cfm dual feed(80508-1) or 670 cfm (80670)or 570 cfm (80570) all four of these carbs are dual feed (they ARE NOT double pumpers )
*spectre dual carb hat (custom cold air ducts )
* extra goodies chrome alt and brackets,power steering pump and aluminum pulleys
*other mods later are dual electric fans
*.this is my 383 build .i hope to be around 400 torque 380hp atleast
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Here's one more viewpoint.
Referring to your list, your significant power adders are:
* displacement
* compression
* camshaft
* heads
* intake
* carb
Your list doesn't mention exhaust, trans or gears.
650 will make a respectable daily driver in the RPM range will use the most while providing reasonable economy if you don't hammer the accelerator. 670 will slightly soften the lower RPM response, but extend the mid-range a few hundred RPM, with a gentle trade-off in economy. I think 750 is too much air for your build and will probably leave you regretting it in the long run.
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*350th trans b&m shift kit with 3.42 or 3.73 gears
* dual 40's flowmaster 2.25 exhaust with x pipe with summit long tube headers
with 32" rear tire 30" front
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OK 600 or a 650 will work 600 better mileage 650 better performance.
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750's are for big blocks. Period.
UH OH I have a 4.3 with a 750 dp blow through carb on it, I guess I better take it off. maybe it will go faster than 10.20's in the 1/4 then lol
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750's are for big blocks. Period.
That statement is pretty bold with no facts to back it up. :-[
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I have very similar specs on my 350 w/o a stroker kit.
it is a '75 block
-vortech heads, edelbrock performer intake
-similar cam to yours
-flat top pistons
-headers, dist, e-fan, exhaust, 5 speed etc.
I have run both the 770sa and the 670sa on the dyno
The 770 ran great out of the box, the 670 needed bigger jets to keep up with the numbers the 770 could do.
I went with the 670sa with bigger jets to keep the vacuum up for better street manners and throttle response.
end results were 393 hp and 432 tq.
I would expect a little more with your engine.
sounds like a very solid set up but don't go too small on the carb, I don't think a 500 could keep up and would be hesitant of a 600.
btw I get 17-21 mpg
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wow :o i like those numbers if my torque and hp hits that range .i will be pleased money well spent .
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wow :o i like those numbers if my torque and hp hits that range .i will be pleased money well spent .
You should do better, one nice improvement (if you haven't asssembeled it yet)with your combo would be flat top pistons; this would keep you under a 10:1 CR and can still run 87 octane. That is how mine is set up but it does make a big difference with 92 octane.
I guesstimate my cr to be about 9.7:1
On a side note; I also run an open spacer between the carb and intake-this keeps the a/f ratio even from bank to bank.
I do have my vacuum advance hooked up and run 31 degrees advanced.
Jet sizes are F:68 R:72. I kept them a little smaller on the primaries for mpg reasons if I take it easy.
Also consider a dyno tune; mine cost $250 but netted another 20 hp. and your engine will be test run and broke in before you go through the trouble of installing it. Oh and its great to see the numbers. Most likely you'll make some of that money back on mpg savings. Then of course post your results here for all to see.