Well it seems like i'm just all full of fun questions tonight It's just I've realized my build is definitely starting to come together (or at least the knowledge base for it) so the questions keep popping up.

This one deals with lifters.

Is there any difference between the lifter for a 302 and a 390? The only difference that i can think of is that the 302 is designed to oil up through the pushrod, but otherwise would fit fine. Are the lifter bodies the same length? (i'm assuming so since some part suppliers have them listed as the same while some have two PN's.)

I'm thinking of a cheap way to come up with roller lifters and a set of ones for a 302 HO are only about $115 a set versus the $500 for the bar link ones designed for the 390.

Is there any reason the 302 roller lifters wouldn't work so long as I made a set of guide bars to keep them from spinning?

Justin

 

Now, (and I could be wrong on this), but didn't the 302 have lifters with a pin in the side of 'em that matches to a groove in the lifter bore?

I also think there are tools that allow you to cut a groove in older 302 blocks to use factory roller lifters. Maybe one of those could be adapted to work on an FE?

Having not had, or measured, a set of 302 lifters I really couldn't tell you how well this would or would not work.

Also keep in mind, I think the lifter bores were not held to as tight a tolerance on non-roller lifter engines as they were on roller lifter engines. This could cause one or more of the lifters to not be perpendicular to the cam, causing the cam to want to walk forward or backward.

 

The 302 roller lifters are longer than flat tappet lifters and have two flat spots on the top of the lifter. The lifter is installed with the flats out of the lifter bore. Then a clip is slid over a pair of the lifters which is then bolted down to the block to keep them from spinning.

And a roller cam is allowed .005 thrust which shouldn't be difficult to achieve with the FE's already having a thrust plate.

Justin

 

Well, give it a try! There's plenty of roller cams available for an FE.

 

Are the lifters even the same diameter?

 

yes- same diameter. That's why i satrted asking. that and if you look in the Isky Cams catalog they list their flat tappet lifters as being for the 390 and the 302.

That's why i was wondering if there was any difference except for the hole that would be drilled in the 302 lifter to allow it to oil through the pushrod. And I know a 390 would be fine with oil at this port since it would just stay in teh lifter or get pushed out up into the valley to drain back.

Justin

 

Justin, yeah, the lifters are the same diameter. The waist is at a differant hieght, and the plunger in the FE lifter has longer travel. Interestingly, the boss '9 also uses the FE lifter. I don't know what happens if you use one where the other belongs. Even if the 302 rollers function just fine, how much is it going to cost you in time and trouble to make link bars to hold the lifters the proper spacing apart ? I don't know if the spread between the lifters is the same between the two engines or not. You might try asking someone like Rabotnik ( survival motorsports ), Barry sells this stuff and I believe he is a site sponsor. DinosaurFan, on work's old cast off 'puter

 

The linkbars for the stock lifters are super easy since they don't actually link the lifters. They just rest over them to keep them from spinning. I'd have to make a "spider" to hold it all together, but i think it'd actually be very doable.

Only thing here is since the waist is at a different height i wonder if they'd pump up correctly.

Would the reduced plunger travel cause any issues so long as I set the pushrod length to take the reduced travel into account?

Justin

 

The "waist" is exactly the next thing I was going to bring up

If it's not at the same height, what're the chances of the lifter cocking in the bore and wearing the bore out faster?

AND - I seriously doubt the distance between lifters will be the same. The FE block is longer (bigger bore spacing) than a small-block. And the head is longer, the distance between valves is SURE to be bigger, etc.

 

Yes, the distance between the lifter bores is greater but the 302 lifters ARE NOT linked. that's why they piqued my interest.

I think i'm just gonna go down to Autozone calipers in hand and ask to see a 390 lifter, a 302 lifter, and a 302 roller lifter. If the waist is pretty close and the lifter heights are the same I think i'm going to give a set a shot, see what happens.

And I'd think the waist heights would have to be drastically different to cause an issue, if they overlap everything should be fine to get the oil feed.

Justin

 

Something to think about in choosing the stock Ford roller lifters: They're OK to 5500 rpms, but anything more and they start to bounce off the lobes. Crane makes stock type replacements that are good to 7500 (in a small block with the right springs) The Crane's retail for about $180.

 

I'm looking for my motor to be all in by 5500, but a margin of error would be nice. Once i start getting serious about this all I'll check them out, until then I'm going to let it bounce around in the back of my head.

Justin