31 replies to this topic

[LXdamo]

Gday Rabs,

Just wondering if you bought your heads complete from COME racing or did you buy them bare?

If you bought them complete,did you have them checked out be fore fitting them up?

I found a heap of issues with the complete 600 series heads that i bought,form hour glassed valve guides to seats being .030" different in height.The stud holes for rocker studs weren't even tapped far enough for the studs that were supplied.Ended up having to swap out springs,locks and retainers to get them to work with .660" of cam lift.

I also had a few  issues with the 396 kit. While not far out,the balance was up to 20grams out to the figures that came with kits.Rod bolts galled in the rods.

 

Hope you didnt have any of the issues i had,but just because your buying from a supposedly reputable company doesnt mean they'll be right!  i suppose it buyer beware as usual!

[MR77LX]

I bought the heads bare and fitted a set of Howard rocker arms.

Im very surprised you had found issues with 600 series. Did u get someone to check them before you fitted them?

Did you speak to COME about this and what did they say?

The only thing i have noticed with my motor is a slight knock on cold start up.

[LXdamo]

I had them checked out by the builder of my engine luckily.I had the stripped down as they getting further porting.

I spoke to COME and they said they were as suprised as me,but then went on to say i/we must have made mistakes in our measuring.

It is all fixed now and am waiting to get some pipes made up then run the thing on the engine dyno.

[Lima31]

Just wondering about the bottom end and whether the stock 2 bolts will hold a 383 ... perhaps 1/2 inch cleveland studs and keep the stock mains caps, or whether the mains absolutely must be converted to 4-bolt for a red holden 383?

 

Particularly if it is only street duties and max of 6000 rpm?

[ozyozyozy]

To way in on a couple of comments.
I have come alloy heads, lucky my machinist did his job, found numerous issues, asked for spring setup to suit a sid roller, gave them the specs, they sent a setup to suit a softer hydraulic roller, just one of the issues.
Have since found out its actually common to see issues with threads/castings/springs.
When questioned they didnt want to come to the party to fix the problems.
I would highly recommend 4 bolt mains on a 383, would on any performance holden v8.
I also agree for the hassles stick with a 355, seen them make 400rwhp, rev to 6500-6700 and are still well mannered for the street, nothing too exotic.
Must consider all elements of the engine not just chuck a bunch of parts at it coz fred says that manifold is awesome jim runs a sick cam.
Compression ratio, cam, manifold, heads, exhaust all work together.