[69FIREBIRD76MM]

I just bought a pair of edelbrock heads 87cc, how can I ID if this are early or later style, I need to buy ARP head bolts and want make sure I buy the right ones. Here are some pictures. Thanks everyone.

[JD311]

End head bolt holes (under valve cover) are sunk down on the early heads. Looks like you have the late ones.

[Held for Ransom]

Just curious, what were the numbers stamped into the head on the last picture?

[69FIREBIRD76MM]

Originally Posted by Held for Ransom

Just curious, what were the numbers stamped into the head on the last picture?

I have no idea. It has more numbers and letters stamped . The seller couldn't tell much about them. Just that they were set up for hyd. roller cam, and the ports look like they were cleaned up. The intake ports measure 2.20"x1.19, looks like the felpro #1233 gaskets fits right on.

[mgarblik]

Those are an exemption order number, ie. EPA number registered in CA to certify those heads as an EPA certified replacement head that will not alter CA's specific emissions laws. Has no real practical meaning other than to make them legal for sale in CA and costing Edelbrock approx. 20K per part number for the exemption.

[Held for Ransom]

That's probably the co. and work order number.
I was wondering about these...

[69FIREBIRD76MM]

Originally Posted by Held for Ransom

That's probably the co. and work order number.
I was wondering about these...

Oops here are the numbers.

D7347

[Tom Vaught]

For sure you have the later style heads, First run and second run E-Heads had the "submerged in oil" end bolt holes (like a factory pontiac Head). (Head bolt head is down inside the end hole casting).

Tom V.

[Garry Sr]

I'm curios why they changed them Tom, I had a set of the early heads and I never ran into any issues.

[Tom Vaught]

Commonality of the head bolts in fewer places was what I was told.

Instead of unique fasteners in more places, The lengths of the later heads is:

Twelve 4.25" long head bolts

Four 4.00" long head bolts

Four 2.25" long head bolts

That means that all 5 bolts (under the Valve Cover) are the same.

http://arpinstructions.com/instructions/190-3605.pdf

The early reads required extra machining operations by Edelbrock for the deeper pocket (early) head bolt locations, 4 different head bolt lengths vs 3 head bolt lengths, etc.

Tom V.

[PAUL K]

Originally Posted by Garry Sr

I'm curios why they changed them Tom, I had a set of the early heads and I never ran into any issues.

I've had heads come through my shop that had been welded in the pocket of the short head bolts holes (they were leaking water), so that might explain why that change was made. Another change was, the new heads require less different length head bolt fasteners. The original I believe used 7 different length bolts/studs, the new design requires 4 (just going by memory) and probably the biggest improvement was reshaping the water circulation holes around the cylinders.

We have not had any obstacles with the original design heads that weren't easily solved. However I really wish they would have designed them to work with 1.65 rockers without modification.

EHTTFMF!

[Garry Sr]

Thanks guys, now that you mention it I did have to helicoil one hole because I screwed up and used the wrong bolt.