Gen6 Cam in a Gen4 BBC - Been There?

Bono454 · Nov 30, 2010

Has anybody fitted the above? I've been handed a hydraulic roller cam (Comp XR294HR) from a ZZ502 and would ideally like to drop it in my Gen4 454. Can this be done positively?

I've been told it can be used happily if you use the timing kit and retainer plate from the ZZ502.. (Eg - Summit 12371053)

BUT.. I also just got sent this response from Comp Cams tech support:

" It doesn't work because of the smaller bolt pattern and needs to have a retainer plate set up for that particular camshaft and the base circles are different for the late model versus the old style camshaft etc."

Can anybody speak to this from first-hand experience? (As opposed to rumour and hunches

Assuming the timing gear swap relates to the 'bolt pattern' but what does "base circles" mean?

The rest of the setup FYI; Holley 750VacSec (3310), AirGap matched to ported ZZ502 rectoval heads #6045, tri-Y headers, 2.5" twin system, T350, 3.5 gears. (Will need to change 2500 stall to 3000 for cam). Don't know compression, internals assumed std 2-bolt 454. Is streetcar with trip to drags few times a year.

Oh, I also heard the standard ZZ502 cam works a treat in a 454.. But this Comp one has a wicked loping note by looks. Anybody seen/heard/driven either?

Cheers heaps in advance guys!!

SIDEWAYS · Nov 30, 2010

Yes, the Gen6 cam bolts into a MK IV block with no issues. In fact, its the way to go. You need a Gen 6 timing set, which comes with the retainer plate and bolts to properly retain the cam. Your block should have 2 tapped holes on the block for this already.

BillK · Dec 1, 2010

Just finished doing a 396. You also have to use the Gen6 timing set. I have done at least 4 of them and had no issues at all.

Bono454 · Dec 1, 2010

OK.. so what is with COMP"s reply then?

And I'm a bit naive in this area sorry, so not sure what "the base circles are different for the late model versus the old style camshaft etc." means?

Is the Summit parts at that link all I need different, or potentially more bits? (inc pushrods etc).

Cheers!!

CMQuickcoupe · Dec 1, 2010

I"m sure you need to run the retrofit lifters because the old block has no provisions to run the spider and dog bone factory setup and your pushrods will be shorter than your old ones also.

awsm502 · Dec 1, 2010

Also, make sure your block is drilled and machined for the thrust plate (retainer plate). Most MKIV's are, but some are not.

And yes you need to use the retrofit lifters.

There was just a Letter to the Editor on this in one of the mags (Hot Rod, Car Craft, or Super Chevy). Basically saying that this will work, given the right parts are used. There is a new double roller timing set that is made for the Gen6 cam, and will fit under the MKIV timing cover (I believe it is a Comp Cams part).

BillK · Dec 2, 2010

Deano,

You have to use the retrofit roller lifters. The early blocks are not machined to accept the Gen6 style roller lifters.

This timing set you linked to looks like the correct one. I did not realize they were that cheap from GM

I have the part numbers at the shop for the retainer plate and the screws, I will try to remember to post them in the morning.

BillK · Dec 2, 2010

Deano,

The plate is GM part number 10168501 and the screws are 14093637 qty 2

SIDEWAYS · Dec 2, 2010

This is the kit from GM - includes timing set and retainer/bolt set. Pretty reasonable too:

http://sdparts.com/details/gm-performance-parts/12371053

awsm502 · Dec 2, 2010

Info on this is in the Dec. 2010 issues of Hot Rod in the Pit Stop section.

Timely, huh?

Bono454 · Dec 17, 2010

Hey guys, just wanted to thank you all SO much for this input.

But the rest of the deal (heads/intake) just fell through due to damage & though simple to you guys, this is just too much brain damage for my little head. Will start looking at a solid flat tappet (designed for MkIV) for simplicity I think.

Cheers heaps again anyhoo

Gen6 Cam in a Gen4 BBC - Been There?

Top Contributors this Month

Recommended Communities