289/302 heads.

Dave Moors

New Member
Dec 7, 2004
4
0
0
HI all,
I've been offered a pair of 302 heads in better condition than my existing (i think) 289 heads that will allow me to get back on the road quite a bit quicker but can anyone tell me where I can find info on the differences between the 2 head types and if I need to do anything to the block?
Thanks
 
  • Sponsors (?)


Yeah, it depends what the heads are out of/what year they are. If you just wanna get the car running, that's a whole other ball of wax, too.

I mean, after toasting a motor, I cleaned the rust off an old shortblock and went to the junkyard to get heads out of anything 302 just to get back on the road. I ended up with heads from a 70-something T-bird and that motor ended up lasting me five years. I saw about 120 on the freeway one night and it didn't sound like it was going to explode. When I swapped it out for a crate motor, the only thing wrong was a leaking front main. It has now been cannibalized into two other motors.
 
so if i put 289 heads on my 302 will it bump compression?

Depends on what 289 heads you're talking about. They're not all the same. The early ones had a small 54 cc chamber. The later ones grew to 58 or 60 I think. The so called 68 Stang "J" code 302 heads were simply recast early 289 heads (C6OE) and had that same small 54 cc chamber, hence the 10.5 to 1 comp ratio. 302 heads had 54, 58, 60, 64 and 79 cc chambers, depending on the head casting.
 
I spoke to the seller and they are allegedly from a 91-94 302 motor. The existing engine i am told came out of a 67 cougar. Can handle the loss of some performance esp if it helps me get on the road sooner. Plus our gas prices are going up again as our government goes all "green".
Thanks for assistance.
 
I could be wrong, because I honestly don't remember for sure, but when I was junkyard-hopping for a set of heads I could use, the later ones had some sort of smog inlet or something. It wasn't that they wouldn't mate to the block, but that there was essentially a hole in the head that needed to be addressed. I chose the oldest set in the yard so that I wouldn't have to deal with any oddities like that.

Once again, I could totally be wrong because I don't remember for sure, but it'd suck to get all the way into it and excited about getting the thing together only to find out you've got another thing to deal with. I hope I'm either wrong or that it's not a big deal.
 
IMHO if you really want to wake up a 289/302 with a stock head than you should be looking for a set of 69-74 351W heads. If a port is too small it may yield velocity from low end torque but it has no performance when it is time to open the throttle, the engine just struggles too much to breath. The 351W's are a great compromise and if you bother with a good port and bowl job it's an outstanding stock head.
 
Posted this same question about the 65 head on a 70 302 on corral.net here was one the only answer so far.

If it is a true 1970 piston, the one with the small dish (not a flat top 4 eyebrow), then the 54cc 289 head is going to bring it up to around 9.5:1. The 1970 set-up would have been using the 58cc head and had around 9:1. So for this geometry, the 4 cc smaller combustion chamber is going to increase Cr by ~ 1/2 a point. this is for the stock configuration and a gasket thickness around .040, deck clearance .012.