cam interchanges

[challengerman]

Guess I'll try this again because I thought it a valid question. There seems to be some difference of opinion as to whether 331-354 cams interchange with 392s. Can anyone clear this up authortatively?

[dodgedifferent2]

i have been told they do not interchange. The lobe seperation are not the same on the 392 as the 354. The 392 has a snout on the end of the cam which the 354 does not.

[George]

The 331 cams have the snouts. The raised deck of the 392 is the cause of the difference in cams, 331 & 354 interchange 392 doesn't.

[firepower354]

They have a couple degrees different lifter bore angles to maintain decent pushrod angles. The passenger half of the engine would have retarded valve timing. I'm sure the actual specs are out there.

[challengerman]

Hi everyone & thanks for the input. I'm hoping to hear more on this. Here's the problem I have right now. I was going to have some cores ground but now I'm really concerned and maybe I need to find a different cam grinder. It seems they have been interchanging 354 and 392 cams for some time. I'm assuming innocently out of ignorance as to the difference. Where could I get specs to straighten them out - or should I look for someone else? There really aren't that many cam grinders that I know of - - .

[johnny5]

I wouldn't mess with a regrind when you can just go out and buy a brand new one that's never been inside an engine...

[Hot Head]

Challengerman:
Hear is some info that might help everyone. Although short deck cams usaually have the long snout (threaded) and tall decks have short (drilled & tapped) snouts, there are short deck, short nose cams (354 and some polys). The way to tell is to hold the cam looking down the length with the gear away from you. Look at lobes number 3 and 4 from the back (gear) end. If they are in almost the same location, it's a tall deck cam. On the other hand, if they are obviously differant, its a short deck cam. That's why the cams will interchange and will run but not run right. This can be a big help at the swap meet too.
Have fun!
Bob Walker

[Bailiesdad]

"Where could I get specs to straighten them out?"

New cores are available for both the short decks and the tall decks, if you want more than 450 460 lift you most likely will need a new core, Isky, Chris Neilson, Racer Brown, Sig Erison and a few others have the different profiles for both.

I would tell your cam grinder to contact one of those to "share" the profile info on the different cams, or just buy two and have them run them through their CamRX and they will see the differences.

OR you can pickup worn cores for them they run 25-35 each all over the place.

Camcraft cams has about 8 different profiles for the cams and also stocks the new cores, last time I talked to them. They charge shops about 75 bucks to regrind one of the stock cores or you can buy new cores and have a custom grind made to your specs.

Racer Brown does the same.. I think Kantor just got a few also.