super charged 340 ???

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mopar3401987

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i was looking at some paxton superchargers for my 340 and was wondering if it will handle 7-8lbs of boost

my 340 current set up
fresh rebuild
.30 over
eagle stock stroke crank (cast)
out of the box closed chambered eddy heads 60779
eddy air gap intake
1 inch hvh spacer
750 prform carb ( will change if i go with a paxton super charger)
cam is a Hughes SMC2336AL Intake Valve Lift Intake .512" Exhaust Valve .518 Intake Duration at .050"223° Exhaust Duration at .050" 236° ( will change if i decide to go with the super charger)
2500 rpm stall
10 to 1 compression
gears posi 3.91
full length headman headers
ignition accel distributor with a REV-N-NATOR box rev limitor set at 5500 rpm
fuel pump is a Edelbrock Performer RPM Street Fuel Pumps 1720 110 gph
Maximum Pressure (psi):6 psi


http://www.jegs.com/i/Paxton/769/12...Lk_RoqtPXYNS1QBTFY0nK6-obaQAQRPtrUaAtsQ8P8HAQ
 
Too much compression with pump gas, i would think? You might be able to swing some thicker head gaskets to help some with that?

You'll be changing the whole character of the engine you have now, so keep that in mind with what you're looking to do...Power vs Drivability vs cost? One plus might be that a well put together combo might require less gear then the 3.91's?
 
yea i was worried 10 to 1 would be a bit much i do know they do sell thicker head gaskets but i have noi idea how much that will drop it ... i aslo do mix 100 octain with some 91 in my tank of gas. i do have two 8 3/4 pigs 3.91 and a 3.23 both posi so i could switch them out. looking for a pro touring car not a drag car just put 4 disk wilwoods on the car. next a hotchkis suspension
 
I would be really concerned about the crankshaft even if you got the compression under control. A stock forged one would be light years better.
 
hummm yea its a 73 340 when i had it rebuilt they told me at the machine shop the cast crank would be plenty strong enough but at the time i wasn't thinking i was going to put a paxton on it .... i kinda regret not spending a bit more money on forged one... :/
 
Cast pistons? If so, I wouldn't. Even at 7-8psi, but that's just me. Wouldn't mess with a cast Eagle crank with boost, either. Cam could work with that split... What's the LCA?
 
mopar3401987 said:
hummm yea its a 73 340 when i had it rebuilt they told me at the machine shop the cast crank would be plenty strong enough but at the time i wasn't thinking i was going to put a paxton on it .... i kinda regret not spending a bit more money on forged one... :/
Click to expand...

I bet witepunkonnitro can hook you up with a forged one.
 
IMO 7-8lbs should be no problem with a cast crank as long as your tune is good. Guys run twice that with stock cast cranks with no trouble. Compression may be a bit much depending on fuel used. Why such low rpm redline on such nicely built 340? I would wind that one out to at least 6k or more.
 

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If you need a complete forged 340 assy. I have one. Was balanced by speed shop. Includes harmonic balancer.
 
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