need advice on shortblocks (which one/where to get it)
06-23-2011, 01:20 PM
#11
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
A 363 is basically a 347 with unshrouded valves =)
Same with a big bore 347, 331 with unshrouded valves.
The trend in newer production engines is towards longer strokes with narrower bores. Makes good torque everywhere and has excellent detonation resistance, but that's also on OHC engines where designers have more leeway in valve placement. Pushrod heads are more limited in valve placement and angle, so the larger bore helps keep the valve from having "dead flow" areas where it's close to the cylinder wall. The large quench areas on pushrod heads help offset the detonation chances from a larger bore by squirting the charge towards the center of the chamber.
If you're going to an aftermarket block, then like Adder said, go with the big bore. The only reason not to would be if you're racing in a class that has a max bore limit.
8:1 big bore 347 with 15+psi on a turbo baby. =)
Same with a big bore 347, 331 with unshrouded valves.
The trend in newer production engines is towards longer strokes with narrower bores. Makes good torque everywhere and has excellent detonation resistance, but that's also on OHC engines where designers have more leeway in valve placement. Pushrod heads are more limited in valve placement and angle, so the larger bore helps keep the valve from having "dead flow" areas where it's close to the cylinder wall. The large quench areas on pushrod heads help offset the detonation chances from a larger bore by squirting the charge towards the center of the chamber.
If you're going to an aftermarket block, then like Adder said, go with the big bore. The only reason not to would be if you're racing in a class that has a max bore limit.
8:1 big bore 347 with 15+psi on a turbo baby. =)
06-24-2011, 02:07 AM
#13
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Thread Starter
Join Date: Oct 2005
Location: Montreal, Canada
Posts: 8,401
i dunno man, the more i think about it the more confused i get... i thought getting some opinions would put things in perspective but it doesn't 
what i need is someone to tell me "do this, this is what you want" but i don't know what i want! maybe i'm spending too much time with my GF.
what i need is someone to tell me "do this, this is what you want" but i don't know what i want! maybe i'm spending too much time with my GF.
06-24-2011, 06:20 PM
#15
M.A.D. Motorsports
Join Date: Jul 2006
Location: Indiana
Posts: 8,014
The only thing I see about upping the cubes with a stroker is the fact that your custom cam and tune won't be the best for it anymore. Of course the cam will work but not to its full potential anymore...hell maybe slightly better but still my point is the cam was for the 302. The tune will have the same affect.....it will work but not be the best for it
06-24-2011, 08:35 PM
#16
4th Gear Member
Join Date: Jul 2008
Location: alabama
Posts: 1,812
I didnt know you could put anything in a 302 but a cam for a 302??? ok ok a 351 also my bad!
It is the wrong statement to say that cam is for a 302 lol! more like you need a better one for your application rather than that, i could see if he was stabbing a 350 camshaft in a 302 then your statement of that cam is for this or that would be fitting!
Dont get your undies in a wod i just felt like sturring the pot!
OP get a better block and build your 331 and boost it til you cant stand it!
It is the wrong statement to say that cam is for a 302 lol! more like you need a better one for your application rather than that, i could see if he was stabbing a 350 camshaft in a 302 then your statement of that cam is for this or that would be fitting!
Dont get your undies in a wod i just felt like sturring the pot!
OP get a better block and build your 331 and boost it til you cant stand it!
06-25-2011, 11:16 AM
#20
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Thread Starter
Join Date: Oct 2005
Location: Montreal, Canada
Posts: 8,401
i know swapping out the h/c/i would net some better gains but that's not really an option (money wise) i like the set up the way it is, i just want a tad more low end and some extra boost... i think considering that, the milder i go the better it should work out. i'm gonna stick with my dart 331 shortblock idea and just play with the pulleys and tune from there. thanks for all the help guys!