Vintage Mustang Forums banner

1 - 5 of 5 Posts

·
Gone but never forgetten
Joined
·
25,239 Posts
Yes, they can, and yes it is IF ... you go with higher compression pistons or shave the heads to offset the compression loss you'd suffer from the bigger combustion chambers of the 351w heads. You'll need to address the head bolt difference (351w uses a 1/2" bolt and the 289/302 uses a 3/8" bolt), but there's many cost effective methods of dealing with that.

I've got 351w heads on my 289. I used 10:1 flat top pistons so as not to have to shave the heads and keep the compression ratio up to around 9.5:1. My best time, to date, is a 14.334 1/4 mile, and that was spinning the tire through most of first gear (traction-lock rear not locking :()
 

·
Registered
Joined
·
7,671 Posts
As Johnpro said, unless you do something to bring the compression back up to where it was with the 302, then your efforts are wasted.

Two other things to consider, (1)the W heads have the same horrible exhaust ports as 302 heads, unless you are capable of removing the thermactor "bump", in the exhaust port then your better off keeping the 302 heads. (2)Only 69-73 W heads have the slightly larger intake ports and valves....
 

·
Registered
Joined
·
10,587 Posts
What year and code 302 and what year 351W heads?

Old performance swap; been done for nearly 30 years AFAIK. It was my first performance modification back in the late 70's when I was street racing.

What else is going on with the engine, performance-wise and what is the budget for this swap?
 

·
Registered
Joined
·
5,066 Posts
1. only 69-73 heads are in play.
2. you must take out the Thermactor bumps. This can be done at home but you will eat a lot of iron filings before you finish ::
3. you need to mill or otherwise get your CR back up to snuff. A straight swap will otherwise cost you about a point in compression.

Bottom line, before there were scads of aftermaket Windsor heads, this was about the only game in town for 302s. Now that everybody and his cousin makes cheap aftermarket heads, its not worth the trouble unless they are free or close to it, and you grind them yourself. Today there r several good aftermarket iron heads that wont cost anymore than prepping the 351s and fall right on your motor.
 
1 - 5 of 5 Posts
Top