302 HO Camshaft
 

I just came upon this board after purchasing a 82' Mercury Capri. I have a question for all you Ford heads. This car came with a 302 H.O. 2 Barrel. My question is that it was rebuilt by a shop about 35,000 miles ago, and it appears that they installed the forged pistions, however it has a, we'll call it "std 302" cam vs. the H.O. Cam. Should I change this out, and what gains would I see. Thankss for any help on this.

H.O. cam differences
 

Without the 'HO' cam, you don't have an HO motor. Although the HO cam runs a tad short on upper-RPM power, it's still miles above the 'stock' cam.

The H.O. cam has a .444 lift vs .379 /.375 for the 'base' 5.0.
Duration is .266/.276 for the H.O. vs .244/.256 for the base 5.0. It makes a difference.

I can't tell you what the exact performance differences would be but it should be noticable, especially if you intend to make performance modifications to the Merc.

Also, the H.O. cam should be steel (as opposed to cast iron), and may require a different distributor gear, as well as a different firing order.

Take care,
-Chris

Personally I wonder if it's a 1982 HO that is being talked about, or a roller HO. What hasn't been mentioned here is that the roller HO cam will require roller valvetrain, and if I'm not mistaken, the camshaft itself won't work with your block. (Roller conversions are made for a different camshaft diameter, aren't they?)

The 1982HO cam is as follows:

.416/.445 198*/208*@.500 and 260*/274* overall.

I think the standard cam back then was the same as the 255

.380/.380 244*/244* overall.

The 1979 5.0's used

.381/.397 244*/256* overall

As far as I'm aware my 84 had the same flat tappet cam. It was called the 2V marine cam. Personally I think it was pretty wimpy. It fell on its face at about 4500. Swap it out for a 268 xtreme energy grind. I talked witha few guys and they said that it would operate well even with the stock heads and it's the largest xtreme energy grind you can run using the matching springs without spring pocket mods. Get rid of the junky 2 barrel and get some headers and exhaust and you'll prolly be a pretty happy camper. Oh yeah, 3.73's wouldn't be a bad idea either.

later