Engine: Avanti R2 1963 engine + Head #535976 and dished pistons

[Leo B]

Hi,
I have Avanti R2 engine + Paxton + Head #535976 + Dished Pistons + Carburetor 3507S + manual 4-speed.
I have started to restore engine and need advice to buy correct parts. I think I need thicker head gasket like Fel-pro 7669. What else do I need to consider with #535976 Head and dished pistons?
My main question is: Do this combo work without special attention?

[DEEPNHOCK]

The 976 head is 58.0cc combustion chamber volume.
That was used on trucks and supercharged engines.
Your supercharger was to make up for the lower static compression ratio.
(opinion)
A thicker composite head gasket will make for a better running engine on today's gasoline.

[64studeavanti]

This combo should give you a static CR of about 7.5:1 with the thick head gaskets, depending on how much the heads were milled and if the block was decked and/or overbored. If you are looking to restore, you will need to locate a set of the correct 1557582 heads, flat top pistons, and shim gaskets. This combo should give you around 9:1 static CR depending on the same as above. Common wisdom suggests that using the thick head gaskets over the shim gaskets yields a difference of about .5 static CR.

[64studeavanti]

Another thought, you may want to double check for the correct camshaft. The "R" series cam does not have the extra lobe casting for the fuel pump.

[Leo B]

The 976 head is 58.0cc combustion chamber volume.
That was used on trucks and supercharged engines.
Your supercharger was to make up for the lower static compression ratio.
(opinion)
A thicker composite head gasket will make for a better running engine on today's gasoline.

Hi Deepnhock. If I undestand correct the 976 head and dished pistons are for Supercharger Golden Hawk. + thicker gasket like Fel-Pro 7669.

https://www.autozone.com/gaskets/head-gasket/studebaker/golden-hawk

So... if I just choose gasket like this all should be ok for the head. Maybe not same power/horses like with R2 head but would work.
Correct?

[Leo B]

This combo should give you a static CR of about 7.5:1 with the thick head gaskets, depending on how much the heads were milled and if the block was decked and/or overbored. If you are looking to restore, you will need to locate a set of the correct 1557582 heads, flat top pistons, and shim gaskets. This combo should give you around 9:1 static CR depending on the same as above. Common wisdom suggests that using the thick head gaskets over the shim gaskets yields a difference of about .5 static CR.

Yes, I would like to have correct R2 Head and pistons. Just hard to find the 1557582 . I like to buy if somebody sells. I think all other parts + pistons are easier to find.

[Leo B]

Hi 64Studeavanti. I dont have Cam near but here is the photo. Correct one? Should be.

[64studeavanti]

Looks correct. Easiest way to verify is to count the lobes. Should have 16. If you have 17, you have non-"R" cam. Post the casting number and we can verify. I have NOS to compare to.

[64studeavanti]

Cam casting number should be 1557663. It is located near the distributor drive end and is in 2 rows. Non "R" cam is 534131.

[Leo B]

Cam casting number should be 1557663. It is located near the distributor drive end and is in 2 rows. Non "R" cam is 534131.

Hi again. Thanks, I really appreciate your effort. All parts are now in machine shop. I will check that later.
I think all are correct R2 parts except the head and pistons are like Golden Hawk ones. Hope this combo works fine with Paxton and R2 carburetor untill I find the R2 Head. Ofcourse with thicker gasket.
The reason having this 976 Head is that previous owner broke Paxton and original head. Instead of trying and waiting to get correct head, the owner installed what was fast to get. Im fresh 3rd owner.

[StudeRich]

I would be ordering the correct R2 Flat Top Pistons unless yours are the Aftermarket Avanti Shallow Dish Pistons instead of '57/'58 GH DEEP Dish, and not worry about the Heads, as they are the SAME compression as the 1557582, and R2's use thin Shim Head Gaskets 1545072 to achieve only 9.5 to 1 Compression with Flat Tops.

If your Country has 92 or better Octane Premium Fuel, it should run fine.

[Leo B]

Hi StudeRich. So that I understand correctly... You recommend to buy Flat Top Pistons R1/R2 and just use thicker gasket and measure Compression close to 9.5/1
Yes. We have 98 Octane and best is Shell V-power 98.5. Here you see pistons I have now. Are these GH Deep Dish you ment?

[Skip Lackie]

Not wishing to hijack this thread, but Leo's comment about having 98 octane fuel available is sure to trigger comments. My memory may be failing, but I seem to recollect an article from the 1970s that noted that North America calculates octane numbers differently than the rest of the world, and that this difference results in a difference of 5 to 6 octane numbers. Somebody correct me if I'm wrong.

[Corbinstein0]

100LL is available at local airports, but Very Expensive.

[Leo B]

Not wishing to hijack this thread, but Leo's comment about having 98 octane fuel available is sure to trigger comments. My memory may be failing, but I seem to recollect an article from the 1970s that noted that North America calculates octane numbers differently than the rest of the world, and that this difference results in a difference of 5 to 6 octane numbers. Somebody correct me if I'm wrong.

Hi Skip. Seems you are right. https://en.wikipedia.org/wiki/Octane_rating

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).

Result ... European 98 will be USA 93.