331 or 347 in a Bronco?
Elder User
Joined: Dec 2003
Posts: 655
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From: Miami
I have heard that about the 347's burning oil and not very reliable. You are pushing that block to it's max. You have to cut the block for the longer stroke of the rods. They do make a 306 kit. If you are looking for realibilty and a daily driver, stay away from the 347. You know what they say, opinions are like A$$&%*(,s. Post your question in the engine forum or go to www.network54.com/Forum/119417
Al
Al
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
go 331 for sure, you will need to either port/polish the heads or get some aftermarket aluminum heads like AFR 165 or 185's to really see the full potential of that motor. because the stock heads are a serious bottleneck .
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
with the cost of fuel i wouldnt go above 9.1 otherwise youll have to run premium and thats crazy expensive right now
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Elder User
Joined: Dec 2003
Posts: 655
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From: Miami
I would'nt waste the money to have them shaved, however make sure the shop checks for warpage of the heads, which they might mill it down a little. Just check for piston to valve clearance during the build! Increasing stroke, and milling of the heads and probably roller rockers which will require longer pushrods, can possibly cause piston to valve clearance issues. Summitracing.com has some nice kits, I also here P.A.W. does too.
Al
Al
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Elder User
Joined: Jan 2004
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From: Northern, Va
My 347 in a 89 Bronco is 9.2 to 1, they all talk about it but never done it I did & w/ probe pistons you will not end up w/ any or the oil problems !!!!! As thay talk abought that I have done !!!!! My engine is a roller motor !! Comp. cams built it for what i was going to use it for, am using it for what i want to do !!!! man it has the power, stick with the 19 lb injecters! W /alum. heads you could go higher up to 10.5 to 1 , I do run high test !!!! Its a work bronco!!!!
Don
Don
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