This is topic how will this combo run? in forum Tech Talk at Northern California Ford Owners  .


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Posted by LUCKY 187 (Member # 4347) on :
 
well i am building a 331 with an aftermarket block.

i got some trickflow r series heads, high ports. 2.08 intake
trickflow box r manifold, thinking of running a 75mm TB.

the cam is 242 254 with a 114. lift is 584.

flat top pistons and the block has a 0 deck. 0.39 mm gasket thickness 4.100 gasket bore. the heads have a 61cc volume.

i am wondering what the CR ratio will be and if this would make good power NA. i am leaning tward throwing 10 psi at it if not. i have some dished pistions if i decide to go that route.
 
Posted by SAV650HAB (Member # 10324) on :
 
sounds like that will be a solid runner [patriot]
 
Posted by 5.0 LsX (Member # 10017) on :
 
Not a boost motor, but should make good power na, get sum juice 4 it
 
Posted by LUCKY 187 (Member # 4347) on :
 
man i am sick of juice lol. expensive and never have it when i need it. what makes it not a boost motor. i can drop compression if i need to?
 
Posted by bottled95GT?? (Member # 1772) on :
 
quote:
Originally posted by LUCKY 187:
man i am sick of juice lol. expensive and never have it when i need it. what makes it not a boost motor. i can drop compression if i need to?
thats it. Comp. for blower friendly motors is generally between 8:1 to 9 at most. [patriot]
 
Posted by turbo50 (Member # 6700) on :
 
what is the cc on the pistons?

even flat tops have like -4 cc etc etc.

didnt notice but you did say 0 deck right?
 
Posted by LUCKY 187 (Member # 4347) on :
 
Yea zero deck. What am I looking for on the pistons


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Posted by blueoval55 (Member # 9787) on :
 
Those pistons are for a 3.400" stroke crankshaft and a 5.315" connecting rod, which makes a 347 cubic inch engine. the compression ratio would be 10.5 to 1, figuring the valve relief's were around 4 cc's.
 
Posted by MauriSSio (Member # 9943) on :
 
so is he building a 347 or 331? or trying to build a 331 with pistons for a 347? or is he building a 331 with pistons for a 347 but using longer rods? whats going on here?!?! LOL

i dont know much about the part numbers for those pistons or the application but that sounds like a pretty stout combo you got going there. Thats a healthy cam for such a small engine!!
 
Posted by blueoval55 (Member # 9787) on :
 
quote:
Originally posted by MauriSSio:
so is he building a 347 or 331? or trying to build a 331 with pistons for a 347? or is he building a 331 with pistons for a 347 but using longer rods? whats going on here?!?! LOL

i dont know much about the part numbers for those pistons or the application but that sounds like a pretty stout combo you got going there. Thats a healthy cam for such a small engine!!
he said he is building a 331, but those pistons have a 1.175" compression height, which is for a 5.315" rod to be used on a 3.4" crank. so, 4.030 bore, 3.4" stroke, and 8 cylinders makes 347 cubic inches.
 
Posted by turbo50 (Member # 6700) on :
 
Seen 331 with 5.315 rods to prevent oil ring intersection but i think they run 927 pin and different 1.26 height blah blah blah blah.

Anyway that is a 347 piston you are showing there and is gonna have some compression with 61cc and zero deck id say 10ish to one. I think it would run like a mofo with the right cam, tune and air/fuel delivery, exhaust etc.

Fuck all that. Those are nice pistons, sell them (tho you probably already paid to have the rotating assembly balanced) and buy some blower pistons if you want lower compression or buy some bigger cc heads.

[ March 06, 2011, 02:09 AM: Message edited by: turbo50 ]
 
Posted by blueoval55 (Member # 9787) on :
 
yes they have pistons for 5.315 rods and 3.250 stroke. but im going off of the pistons that he has. those pistons do use a .927 pin, because most crankshafts use the 2.100" rod journal. the compression using those pistons, zero deck, 61cc chambers, .039" head gasket with a 4.100 gasket bore, is 10.6. that is figured using the 3.4" stroke that those pistons are made for. with a 3.250" stoke the compression is 10.2. not a blower friendy compressoin ratio as was said before.
 
Posted by blueoval55 (Member # 9787) on :
 
alrighty, my bad. i take that back. i was going off the piston manufacture's website which says they are for a 347, using a 5.315 rod and a 3.4 stroke. after figuring it out on paper, using a 3.250 stroke crank, and a 5.4 rod and the pistons that go in the box that was pictured, it would make a 331, with the pistons .010" in the hole, however zero decked it would still net a 10.2 to 1 compression ratio.
 
Posted by LUCKY 187 (Member # 4347) on :
 
What size TB would you recommend for that. I'm leaning on keeping these pistons and going NA.
 
Posted by MauriSSio (Member # 9943) on :
 
70mm?
 
Posted by turbo50 (Member # 6700) on :
 
quote:
Originally posted by LUCKY 187:
What size TB would you recommend for that. I'm leaning on keeping these pistons and going NA.
Id use a good wrist pin and have some head work done, or flowed so you know where you are at. Port match the intake and stick a nasty solid roller in it.
 




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