This is topic 302 block vs. 351 block in forum Tech Talk at Northern California Ford Owners  .


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Posted by The Nick (Member # 2244) on :
 
I've got a sort of simple question. Exactly how compatible/interchangable are the parts for these motors. I've got a set of TFS heads, intake, and cam and all other supporting parts, but the stock short block's got 140+k and when she lets go (and I pray all the expensive parts aren't damaged) I'd be interested in using a 351 as a starting point. Will these parts match right up or are there any other kinds of things that need to be done?
 
Posted by Fostang (Member # 3752) on :
 
swap pan, swap headers, swap accesory brackets, swap motor mounts.

The cam will work if the block is a roller or converted to roller.

Heads will work.

Upper intake will work lower will not.

Need a correct distriburator for efi.

This is all I can think off right now.
 
Posted by The Nick (Member # 2244) on :
 
Another question. If I go to carb instead of efi, will it be smogable or does it have to stay with the factory stuff?
 
Posted by Fostang (Member # 3752) on :
 
either way it will not be smogable.
 
Posted by 87 Saleen (Member # 1549) on :
 
"302 parts on a 351 will make 302 power" - ???


u said it was just a starting point right? smog is a PITA!
 
Posted by The Nick (Member # 2244) on :
 
quote:
Originally posted by 87 Saleen:
"302 parts on a 351 will make 302 power" - ???


u said it was just a starting point right? smog is a PITA!
Yeah, if I do the 351, its not going to stay a 351. The only 302 parts I'd be interested in swapping over are the heads, cam, intake(maybe) and all the performance stuff. Why would it not be smoggable with the 351? Is it because it won't pass the sniffer or it won't pass the visual? I have a hard time believing that a smog tech is going to recognize the external differences of a 351 to a 302.
 
Posted by Wolfie351 (Member # 651) on :
 
Even a die-hard Ford guy has a hard time telling a 302 from a 351 at first glance. When the two are side by side the difference between manifold widths is obvious, but sitting there alone is another story. No corner gas station smog tech is going to be able to tell. The tricky part is the swap headers, you'd need to use the E.O. # off a 302 header.
 
Posted by cheap (Member # 858) on :
 
It's against the law to swap in a motor that is older than the vehicle (ie a '90 engine in a '91) and it's also illegal to swap in a motor that wasn't offered as an OEM option, smogwise at least. Like they said though, it's hard to tell the difference if the engine is by itself.

Are the timing chain covers the same? Also some distributor gears are different and need to be changed, and the fox power steering/AC pump brackets aren't interchangeable (*edit oops just saw that was already listed; also 302 motor mounts will work).

And you're crazy if you think you can put a carb on an EFI-original engine and be smog legal.

[ September 05, 2004, 08:27 PM: Message edited by: cheap ]
 
Posted by phildog (Member # 1214) on :
 
Really a nice swap, stock 302 motor mounts, get a rebuilt 351 truck distributor from Napa, give them a 302 core in exchange, (they won't know the difference), get the dist gear changed over to steel to work with a HR cam. Conversion headers are needed of course, you will have to cut the crossovers on the fuel rails and use fuel injection rubber line instea. Cut the EGR tube in half and connect it with high temp hose. Some other odds and ends of course like everyone said. It really isnt that hard to do the 351, I dont know why everyone says its easier to convert to carb, but what do I know, I've only done the FI 351 conversion myself. A mild 351 will be a hell of a lot of fun with the extra torque
 




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