how will these parts compliment eachother?

68RustBucket

New Member
Sep 27, 2003
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Linwood, NJ
CHP 347 Street Fighter shortblock (not sure exactly what the cam is)
AFR 185cc heads (are 185's too much?)
Weiand Stealth intake (or Performer RPM)
Road Demon 625 (too little, too much, just right?)

i don't need HP estimates. i just wanna know if certain parts may flow too much, restrict others, or what. i'll have an exhaust system to compliment the engine well.
 
You can't go wrong with either of the AFRs. Big difference is the intake flow rating. You may give up some low end torque to gain high RPM HP with the 185s. But with the 347, you will probably not miss it. The added cubes really make a difference down low. 165s are a bit cheaper.


Looks like you are right in the Ballpark for the Carb and the intake combo.

(CID * MRPM) / 3456 = CFM @ 100%VE

347 * 6500 / 3456 = 653 CFM at 100% volumetric efficiency.

CFM_formula.webp
 

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Here are the specs on my 347 (CHP shortblock) with their wussiest cam, Trick Flow twisted Wedge heads, Weiand Stealth intake, 650 Holley double pumper (originally had a 750 which was too much). You can read about all my specs, dyno nfo, etc on my website: http://www.2mfffabshop.com/

Oh, and nice choice of trannys in your sig :nice:
 
looks like you figured a good combo there. at best you may decide in the future you want to run a slightly bigger carb, but work with what you have for now as it will serve you well.
 
That combo sounds great...too bad you dont know the cam though. However, id see if CHP would put in an xe274hr cam from compcams. That cam, those heads, and an RPM intake make BIG BIG power. its very streetable too. I dont think you have too much carb. You could probably even go with a 650 speed demon. Remember, the 625 road demon flows more than 625 cfm...if its like other demon carbs.
 
compcam's catalog (on their website) says that the XE274HR is for EFI motors, whereas mine is going to be carbed. would that be a problem at all? i had planned on going with the compcams XE274H if i was just rebuilding the 289, so that's a great suggestion for the 347.

would the cam selection depend on the fuel system like they say?
 
No, it will not. What that site should read is the XE274HR camshaft is for late model roller blocks. Most late model roller blocks are EFI; however, a carb is fine.

I have a friend with a 347, carb'd, running that particular camshaft.

If you take a look on the AFR website, they give a list of combinations with different heads/camshafts/intakes/Carburetors with different power bands. Take a look their.