Using grooved 396 cam in a later block?

[shoedoos]

History: Bought a Lunati Hyd Roller and had it grooved at the machine shop so it could be used in an early 396. Now want to use that cam in a 427 which doesn't require the grooved cam bearing or oil slot in the rear journal.

Any issues?

[blykins]

I can't see how there would be an issue, but I will defer to the guys who specialize in Chevy stuff.

Every Ford FE camshaft is grooved on journals 2 & 4. The only FE's that need those grooves are 427's. You can jam those cams in any FE out there, whether it's a 352, 390, 410, 428, etc.

[Walter R. Malik]

here is no issue ... the problem arises when a cam with no groove is used in an early block which needs one.

[pamotorman]

it could cause a big internal oil leak at that bearing and I always soldered the original cam bearing hole shut and drilled a 1/16" dia hole for oil

[bigmike]

Back in the 1970s and early 80s GM sold a lot of the real L88 427 cams. Because they were fairly cheap and really make a BB car with 4:10 or better gears haul. I still have a NOS one around here somewhere. These had the rear groove already in it. At least 1/3 of the area BBC street/strip guys used the GM L88 cams in 427 and late 60s 396 back than in my area. You will want to use the non grooved cam bearing in this case.

[Little Mouse]

Pamotorman is right did this on a 454 back in 74.

[cknight]

it could cause a big internal oil leak at that bearing and I always soldered the original cam bearing hole shut and drilled a 1/16" dia hole for oil

This is an urban legend perpetrated by a well known tech writer in an article for a very popular performance automotive magazine in 1967. The only way a "massive oil leak" can occur is if someone machined their own groove WAY too deep and intersected one of the vent holes at the rear of the cam. The correct groove for the 1965-1966 blocks should be centered on the rear journal, and be 3/16" wide, and 7/64" deep. No issues when used in the later blocks. You'll lose a bit of surface area, but nothing of any consequence. Regards, Chase

[andyf]

I just trashed a bearing in my engine by using a grooved cam. I've done it before without an issue but the oiling system in my current engine is "tuned up" in an effort to save power. So the moral of the story is that a marginal oiling system might not be able to handle the extra oil bled off from that cam bearing. My engine ate the #4 main bearing. Oil pressure was fine and all of the other bearings look good. Engine worked fine with a non grooved cam but bearing went away almost immediately after switching cams.

[pamotorman]

it could cause a big internal oil leak at that bearing and I always soldered the original cam bearing hole shut and drilled a 1/16" dia hole for oil

This is an urban legend perpetrated by a well known tech writer in an article for a very popular performance automotive magazine in 1967. The only way a "massive oil leak" can occur is if someone machined their own groove WAY too deep and intersected one of the vent holes at the rear of the cam. The correct groove for the 1965-1966 blocks should be centered on the rear journal, and be 3/16" wide, and 7/64" deep. No issues when used in the later blocks. You'll lose a bit of surface area, but nothing of any consequence. Regards, Chase

he may have heard that from the guys at GM tech center because that is who told me to mod the cam bearing on race engines

[Walter R. Malik]

I just trashed a bearing in my engine by using a grooved cam. I've done it before without an issue but the oiling system in my current engine is "tuned up" in an effort to save power. So the moral of the story is that a marginal oiling system might not be able to handle the extra oil bled off from that cam bearing. My engine ate the #4 main bearing. Oil pressure was fine and all of the other bearings look good. Engine worked fine with a non grooved cam but bearing went away almost immediately after switching cams.

Oil pressure drop doesn't matter how big the groove is ... the oil loss can only be what can flow through that 5/64" hole in that bearing. A whole bunch more oil than that goes to the lifter gallery supply holes in the block; one leading past the distributor hole.
With some newer replacement bearings the hole is already less than .100".

[pamotorman]

the amount of oil that get thru the cam bearing is restricted because the solid cam journal is pushing down on the oil hole closing it off. when you used a grooved cam the oil flows freely as noting restricts the flow coming into the area.

[Walter R. Malik]

the amount of oil that get thru the cam bearing is restricted because the solid cam journal is pushing down on the oil hole closing it off. when you used a grooved cam the oil flows freely as noting restricts the flow coming into the area.

STILL ... no more oil flow than what can pass through that sized hole.
However, cam bearing clearance in front and behind the groove would probably still be the limiting factor.