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used 351

craigs67

Sr. Member
Joined
Dec 15, 2001
Messages
450
Loc.
Juneau Alaska
I am looking to get a used running efi 351 what comp. ratio should I be shooting for and also what wiring and acc do I need.

Thanks Craig
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
My preference on compression ratio is go as high as you can. I have 11:1 and it is great. Just need premium fuel all the time and keep it in tune.

Being that you are looking at used engines, your choices will be rather limited. Factory engines are 8.8:1 for the Bronco, E150, F150 engines and 8.3:1 for the E/F 250/350 engines (at least the later ones). Earlier were mostly all 8.3:1 unless you get real early ones which were 9:1 or 10.5:1. You probably won't have much choice on compression ratios.

Is tis engine to replace a 302? IF so then little is needed. I would get the intake as it won't carry over. Any other details should be available in the 351W swap section of the tech articles.
 
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craigs67

craigs67

Sr. Member
Joined
Dec 15, 2001
Messages
450
Loc.
Juneau Alaska
351

Thanks I will check the swap section. I was wondering what I should look for on the comp. test at the wrecking yard they ranged from 150 to 180 I think.


Thanks Craig
 
Last edited:

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
Although you would think they would match, compression ratio and cranking compression don't.

simply put, look for high and even numbers. Even is important, even if there gauge lies a little (reads 180 when it is really only 150) eveness across all the holes is a good thing. Usually, the higher the cranking compression the better the torque is off idle.
 
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