I'm about to do a re-gasket job on my all original '95 300 with 252k on the clock. I just read about the Chevy rockers on the older 300's... is there a cheap upgrade like that for the later EFI 300s?

I used to have Crane Gold Race roller rockers on a high performance 300 I built up years ago. Those were nice rockers but cost some bucks back then! $$$$ plus the screw in studs and all the other goodies... sheesh what a pricey motor that was. Totally fun though.

 

You can use ford 3.8 v6 rockers on it, look for some at a salvage yard or the mustang forums classifieds, I know the v6 mustang guys replace their stockers with rollers, I'm sure you can find someone selling them pretty cheap. I just put Harland Sharp rollers on my truck, pn S40173A, there not cheap though. I also had to dimple the valve cover in the center where it dips down under the efi intake, other than that they basically bolted right on. I say "basically" because i had to shim the rockers up but my head has been cut .060". If you havnt surfaced your head I'll bet they would bolt up.

 

So, what would making this change result in, more power, better mpg?

 

The stock ratio is 1.6 so changing to a 1.73 or 1.8 ratio rocker gives a little bit more cam lift plus some reduction in friction from the roller rocker...how much is debatable, 5 people will have 5 different opinions on roller rockers. They should net you a little bit of both but it isnt going to be alot.

 

Hey 9D1, thanks for the tip! Do you know approximately what ratio those rockers are?

 

No problem CJ...The v6 rockers are 1.73 and they have a roller trunion but not a roller tip, your stockers are 1.6. With a factory cam you would increase your lift from about .400 to .430. If you havent, check out ford six performance.com, alot of carbed stuff but plenty of info. the bigsix faq thread is a good read.

 

Hey 9D1,

Ran down to the junkyard today and got a set in like new condition for only 30 bucks. They came out of a low mileage '97 3.8. I can definitely see the difference in the shape of the rocker.

Before I install this, I just wanted to double check that these are a bolt on, torque to spec, deal and drive. I don't want to button this thing up and realize I needed shims, funky pushrods or anything like that. I'm just being extra careful is all.

From just looking at it, as long as I use the Mustang rocker arm, and my original 300 bolt to snug it all up, it looks like it should work no prob.

Thanks again for your help and i'll let everyone know how it turned out.

-Chris

 

Well I installed the first two rocker arms, torqued them to spec and there is no way these will work.

You can move the rocker up and down a good 1/8th inch and they wiggle all over the place.

Maybe I missed something, but I need to be at work tomorrow and don't want to tear back into this thing. I'll do it when I build up another motor I guess.

What I tried:

I used the Mustang rocker arm, the Mustang pivot block, and the 300 bolt because the Mustang bolt was much longer. The only thing I didn't try was using the 300 pivot block with the Mustang rocker. I'm not going to mix parts with different wear patterns though. Plus, I put both pivot blocks on a flat piece of steel and they were exactly the same height. So in hindsight, that wouldn't have worked anyway. Looks like I needed some sort of shim, or longer pushrods. If I have to buy custom pushrods, there goes the "cheap" part of the equation.

If anyone out there is considering this as an upgrade, do your homework, it's not a simple bolt on.

-Chris

 

I thought the 3.8/4.2 V6 used the same rockers as the 302
regards
rikard

 

The 3.8 and 4.2 share the same rocker, and none of them have a bearing in them as stated above. They all have a pivot block.

The 302 rocker is different from the 3.8/4.2/4.9

I went to autozone's website and started putting a bunch of different years into their system and pulled part numbers. From what I could tell all 3.8/4.2s use the same rocker from start to finish. There is no magical year.


9D1 - Where did you read about this swap?