[semperfi48103]

This is the first time i have torn down an engine. I got a 351W from my friend for free:thumbup :thumbup :thumbup . (he got it from his brother 84 bronc 351 just like mine.) the pistons say .040 does that mean that the block has been bored .040 over already. from what i can tell it has been rebuilt. what else should i look for. i want to rebuild it as close to stock as possible with out getting to far extreme. i want to get experience from this one and rebuild the one in my bronc for a 68 mustang that i am dreaming of. :rockon The crank has some roughness on the connecting rod journals and the pistons were in good shape till it sat for 5 years. i also have some questions about the cam and other stuff. i have searched and not really found the answes i am looking for if anyone wants to chat about rebuilding engines IM me

 

[MikE2]

The 040 on the pistons means its already been bored 40 over. You could get 60 over pistons, but if it were me I would find a virgin block. On some engines you could bore them 120 over, but most of them are early blocks with heavy walls and I highly doubt a 84 351 is one of them. I'm sure many people run 60 over pistons in 351 without a problem, I'm just saying if it was me I wouldn't do it

 

[monkeyhouse]

true, if you bore a block too much, they will over heat faster and easier and the cylinder walls are more prone to break. thats why you should stay away from blocks like the 400 SB. i think it would be a good idea also to start with a new block. no telling how much hell that old block from your friend has been through( nothing against the guy ), could have a hairline fracture somewhere for all you know.

i read you want it pretty much as stock as possible. jegs and summit have a few 351 short and long blocks. you could look at junkyards and ebay also.

 

[483/499_302Bronco]

by all means if you can get a virgin block, get it. but you can't beat the price you paid(free). get someone to check out the engine with you so they can show you things to look for. if you dont need to bore the engine out anymore then just do a basic rebuild with a few goodies. i would suggest ARP rod bolt, head studs, and main studs. some may call that over kill for a street engine but you wont have any worries about your rotating assembly, especially if you throw clevite 77 bearings into the mix also. as for a cam, i know that you can go up to .500" lift without any problems.

 

[slider]

I would at least run the crank by your local machinist. If it's trashed, my assumption would be the rest of the engine needs major help.