I,ve got an 85 150 4x4 302 5.0l and I have been reading stuff about the 302 boss which is a Windsor 302 small block with a Cleveland 363 small block head so I was wondering if I could drop a 351 small block head on my 302 and what would all have to go into it besides swapping the pistons like would I have to upgrade my trans cams belts or anything else... Thanks

 

The 302 and 351 Windsor engines uses the same heads.

 

Ok cool so the only difference between the 302 and 351 is the 351 is taller? So would I get any more power or not enough to make it worth my time?

 

You can also ask in the various Engine forums:

Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W) - Ford Truck Enthusiasts Forums
335 Series- 5.8/351M, 6.6/400, 351 Cleveland - Ford Truck Enthusiasts Forums

 

The only problem is in going to 302 heads on a 351 since some of the 302 heads had smaller bolt holes. But, going from a 302 head to a 351 head is duck soup.

However, make sure you get a head with the right sized combustion chambers. Too large of a chamber will drop your compression ratio dramatically. Too small of a chamber increases it to the point you'll have detonation. So, do your homework.

As for a Boss 302 in a truck, that's a bad idea. The Boss 302 had huge intake passages and didn't make power until high RPM. A truck needs low RPM power to move heavy loads, and even the truck itself is far heavier than the Mustang the Boss was in.

In my estimation Lariat has gone the best way by using Thumper's heads, which flow plenty of intake and exhaust but keep the velocity up on the intake so low end power isn't compromised. That's one of the blessings and curses of the small block - lots of heads available but many of them not compatible with a truck's needs. Again, do your homework.

 

Good estimation, Gary. And thanks for the compliment!

That is exactly why I went with the Thumper E7 cast iron heads. I found that most other aftermarket heads, and the Boss 302 heads, give more power up high, but sacrifice down low. That means high horsepower and less low end torque. This is great for a light car, like a Mustang, but it hurts low end performance and torque when you have a heavy full size truck powered by a relatively small engine.

 

I missed that response - maybe as I was responding as I'm sloooow. Anyway, if the only change you are making is the heads then I think it won't be worth your time. A head change should be done in conjunction with other changes like a cam, intake, and exhaust. Let me say it like this: Ford knew the heads were restrictive so didn't worry about the intake or the exhaust being restrictive. If you remove the restriction in the heads you'll still have the restriction in the intake and exhaust and won't gain that much.

But, if you are running the stock EFI you have another problem as that system doesn't lend itself to significant changes. And, if you have to pass emissions testing you can't make big changes either. So, maybe you should tell us about your engine and your needs re emissions testing?

Lariat - Can't you find a thumbs-up with the thumb on the other side? Fonzie was right-handed. Anyway, you are welcome. I did a lot of research on heads when I was porting the D8's and came to the conclusion that Thumper's heads are a good choice.

 

My truck is old enough that I don't have to pass emissions in WA so that's not a concern everything is stock so far but im what I'm looking for is more hp/torque so I'm open to suggestions what can you tell me about the thumper heads? or should I ask lariet that? I don't plan on hauling trailers regularly but I work Construction so I haul some heavy loads sometimes and I do a little 4x4ing so I would like some more power for that

 

Sorry bout the last part I'm on my iPod and didn't see that...

 

I'm not sure why people are talking about the 351W heads when you specified the Cleveland style heads. The original Boss 302 uses a Cleveland style head. If that's the route you are wanting to go, it's not worth it in a truck, maybe a track car that runs in the high rpm's a lot, but not a truck. The Boss motors don't really start breathing and making power until the 6000 rpm range. Same as the 4V 351 Clevelands.

The Boss 302 uses a different block(4 bolt on 2,3,4), rods(different length), pistons, heads, intake, crank(different stroke than a standard 302), etc, etc, than a regular 302. There is basically nothing that is the same.

If you do plan on doing this, you are going to have to modify the Cleveland heads to work with your production block (it's not just a bolt on and go). Also the Boss intakes are going to run you at least $300-500.

I don't mean to discourage you, but your money is better spent on some good aftermarket heads and a set of forged pistons.

As for using 351Windsor heads, unless you get a set of '69 heads or the '69 marine heads, or a few other older castings, they are the same as the 302 heads(We've checked and measured). BUT, if you go that route, just order the head bolts from ARP(not cheap) that come with the adapters to run the the smaller bolts with the larger bolt holes.

If you are just looking for a little more power, upgrade to a 351W which are still plentiful. OR just throw a big-block in it.