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Ford 351W Heads on 302?

37K views 35 replies 14 participants last post by  mmason1 
#1 ·
Will 351W Heads fit on a 302? It might depend on the year but im not sure.. the heads i think are 70's but not sure about the block. Any information would be most helpful :thumbup:
 
#2 ·
I used 1 '69 and 1 '70 351W head on a '77 302 block back in about '82.
the only difference, I believe, is that the 351 uses 1/2" bolts, where the 302 uses 7/16" bolt.
The only issue is that the head bolts will not fit the holes snugley, but the alignment rings will hold the heads in the proper location.
 
#5 ·
351W heads on a 302W

The 351 heads have larger ports AND a larger combustion chamber, so compression will drop somewhat. Compensation for this can be done in two ways: higher deck height pistons or milling (surfacing) the heads. The piston change is the most desirable as you would not be changing the intake bolt alignment by lowering the head position on the block. This is especially critical on the small block Ford as the intake bolts are vertical.
Also the 351W intake manifold gasket must be installed to prevent coolant leaks due to the differences in the coolant outlet(s) at the ends of the intake side of the head. The 302W has a small, rectangular-shaped coolant port, where as the 351W has an "L" shaped port.
Make sure you place the head gasket on the block the correct way or else the engine will over heat in about 5 minutes.
Good luck!
 
#8 · (Edited)
You're correct. The BLOCK has a taller deck height, requiring the wider manifold. The heads are the same.
I used 351W heads on a 302 block with a 302 intake and no special spacers or other magic.
PS: from your source:
"However, both series of engines use the same bore spacing and the bolt patterns are the same, so 289/302/351 heads will interchange."
 
#10 ·
johnnya said:
You're correct. The BLOCK has a taller deck height, requiring the wider manifold. The heads are the same.
I used 351W heads on a 302 block with a 302 intake and no special spacers or other magic.
PS: from your source:
"However, both series of engines use the same bore spacing and the bolt patterns are the same, so 289/302/351 heads will interchange."
This is correct. The only difference is that 351W heads have bigger bolt holes where it bolts to the block.

All 351W heads are not equal. I'm not sure which year but the later 351s had the same size valves and ports as the 302s.

Danny
 
#11 ·
Frank Valentino got it right !!!

Dimensionally, the 289, 302 and 302/5.0 are identical.

There are several sources for the required bolt bushings - this is Summit's:http://store.summitracing.com/egnsearch.asp?Ntt=ford+heads&N=700+115+4294851755&Ntk=KeywordSearch

This is Summit with a TFS head - and what they fit: http://store.summitracing.com/partdetail.asp?part=TFS-51400004&view=32&N=700+4294867081

You need the right gaskets: head, intake and exhaust.

You will lose compression - but in today's world, might not be a bad thing. If you mill the head for compression, the intake will need it as well.

Look for stock Ford heads D0OE-C or G, or C9OE-B or D. They have the biggest valves though some have a hump in the exhaust port that should come out with a grinder. Don't worry about plugging the hole that is in the hump.

Dave W
 
#14 ·
351 heads

Irelands child said:
What hole/hump in the GT40P heads exhaust? Mine don't have either nor have any I've seen. That hole is part of the EGR system/air pump for carbed engines.Later 302/5.0 engines don't have that.
the early 351w heads have larger int and ex valves,you may run into piston to valve isue as 302 with flat top pistons,they have smaller reliefs,after 1971they went to small 302 valv size.re the head bolt get hardened flat washers for the302 bolts,or summit has the corect 1s,if not you will crack the heads or the bolts will migrate into the 1/2 in holesand you will blow head gasket,like preveous posts the manifolds will fit fine,but use the corect intake gaskets or water will leak.
 
#16 ·
Way too many variables for a complete answer - but there are a few considerations. Do your pistons have eyebrow reliefs and are they big enough for the original diameter 351W valves, are the pistons dished instead of having eyebrows, do you have cam lift in excess of .500, what ratio rocker arms are you using - beyond the 1.6 normal ratio, that .500 lift will become ~.530 with 1.7s ???? And many of those questions - can't really be answered with total certainty with out an engine tear down and knowing your parts.

Now, a 90% chance is that you wont have any problem provided you don't do any more head machining then truing it up - say .005 to .010. Much beyond that, you get involved with intake manifold machining to match the lower intake runners.

It just isn't simple when you take an apple and add an orange to it :sweat: :sweat:
 
#17 ·
Well to tell the truth I'm fairly new to the performance engine building thing. I have built engines but only stock. So ive been researching and I plan to shave the heads by .010 and the piston will be stock with the 4 valve reliefs. I plan to use a tfs stage 1 cam. And i believe that shave should give a 351w a 59cc? Thats pretty much everything ive come to after hours x1000000 of research
somebody make adjustments please if need be ?
 
#19 ·
That's a start on knowing what's inside an engine :D Believe it or not, there really are some folks here that know Fords instead of the 'belly button' and most much better then me. With that said, we'll help as much as possible.

With that camshaft - do a good clearance check on the exhaust as you are at .510 lift and are planning a .010 skim cut, bringing the entire assembly closer to the piston. Of course, a wrong head gasket thickness can negate anything you gain - stick with something like a Fel-Pro Q10112 and not something like a usual car parts house like a Victor or McCord. While those are both good products, are for a conventional performance grocery getter. You also need an intake gasket that matches the manifold and the heads - there are different water passages. I use the Fel-Pro Q1250 which is a 'universal' for both 302/5.0 and a 351W.

And yep, these gaskets have gotten expensive, but they work
 
#20 ·
A lot

of these comments are blown out of proportion i have done many 351 swaps in the 70,s and it was easier than a sbc Chevy, If you work with fords you get to know which parts and changes to make. It is not a magic or tough thing to do the swap. Most of this comes from ignorance of the engine and parts
 
#21 ·
rsfyj - what positive comments have you made to this gentleman? You continue on various threads to knock others efforts to guide someone. Quite frankly, my readings of your various postings do not lend you any credibility.

As far as doing 'many' 351 swaps - did you bother to read the information of Mr Mason's part of thread or just jump in. He is adding 351W heads to a 302/5.0 NOT doing an engine swap
 
#24 ·
Yes, 351W heads will fit on the 302 engine. The head bolt holes are bigger than the 289\302. I did this many years ago. There is special bolts made for the swap that come with hardned washers to make it work. Back then (early 70,s) I was able to get them from the Ford Dealer through their Muscle Parts Program. I am pretty sure bolts can be bought most anywhere hot rod parts are sold. In case you need to know, the camshaft also will fit, however you MUST change the firing order on the distributor cap to make that work. Good luck and have fun. :welcome:
 
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