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Discussion Starter · #1 ·
I am trying to degree the cam in my street 355. The cam is supposed to be installed at 106. I can either get 104.5 or 108. Since this is a 4 speed street car with 4.10 gears, I am thinking I could leave it at 108 and it would be fine. How drastic is the powerband shift for retarding the cam 2 degrees from recommended? I haven't installed a cam retarded before so I was just wondering.
 

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The extra advance is better in 9 out of 10 cases. many times even more advance is better yet ( like 6 to 8 degrees )


JOE SHERMAN RACING ENGINES
 

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I would do the 104.5. The only time I have experienced retarding the cam to et better is with big nitrous engines.

The timing chain will stretch and the 1.5 degrees will be 106 with some street driving. Do you have plenty of valve/piston clearance? For each degree I have found about .010 clearance depending on which way you go, at least on a 1.7 ratio rocker on a bbc.
For a sbc it may be slightly less.

Edit: I guess I had better ask what the lobe separation of the cam is? If the cam is ground on 110 and you have 5.5 degrees advance I would go with the 108. If it is ground on 106 and you have 1.5 then I would do the 104.5. I have found that almost all the time 3-4 degrees advance works best if the cam is correct for the engine.
 

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Discussion Starter · #4 ·
I would do the 104.5. The only time I have experienced retarding the cam to et better is with big nitrous engines.

The timing chain will stretch and the 1.5 degrees will be 106 with some street driving. Do you have plenty of valve/piston clearance? For each degree I have found about .010 clearance depending on which way you go, at least on a 1.7 ratio rocker on a bbc.
For a sbc it may be slightly less.

Edit: I guess I had better ask what the lobe separation of the cam is? If the cam is ground on 110 and you have 5.5 degrees advance I would go with the 108. If it is ground on 106 and you have 1.5 then I would do the 104.5. I have found that almost all the time 3-4 degrees advance works best if the cam is correct for the engine.
The lobe separation for this cam is 110. The cam ICL is 106 which is supposed to give it 4 degrees advance already. This is why I thought 108 would be ok.
 

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A machine shop put my Ultradyne in bass ackwards -7. Harold was adamant about running it advanced. So after checking it using Harold's quick n dirty method, I simply flipped the offset bushing in the timing gear around and got +7.

While Harold said the cam always made more power at +4, I'll tell you the lil 427 pushed near 530 HP that way.

So I have to agree with the folks at Joe Sherman racing. Retard is not good, adv is. In fact, I had a 110 LSA cam with the ICL at 102, and it SCREAMED!

104.5 IS the correct answer IMHO. I had mine set there with the new rebuild ( same cam,), and I almost wish I had kept the 101.5/102 setting. Even the machinist said, man, it should be 104, not 101, as did Harold, yet... it kicked azz at +7 .....????

4/5 speed car fwiw. And the +7 deal was with GM 074 rect port heads ( which were done up well), and the engine never ran out of steam at its theorectical limit of 6700. So, the whole notion of losing top end is suspect to me.

No doubt in my military mind 104.5

I'm almost praying my timing cover starts to leak oil, giving me a reason to get in there and advance the cam even more, or "too much" as many would say. Can't comment on powerband, only that there was more "area under the curve" with the cam so far advanced, so it made more bacon.
 

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The lobe separation for this cam is 110. The cam ICL is 106 which is supposed to give it 4 degrees advance already. This is why I thought 108 would be ok.
I would agree on the 108 if the LS is 110. I would guess the duration to be in the 240-250 range. That small of a cam should not need 5.5 degrees advance. Putting it in at 108 would make it more tolerant of lower octane fuel.
 

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Discussion Starter · #8 · (Edited)
Its small it's 231/239. Its the Lunati Voodoo 60122, or 60112, whatever the retro fit cam is.
 

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104 man, dont over think it. If it's a Harold Brookshire assymtrical inverted flank grind , advance the heck out of it. The cam I spoke of was his 276/284F10, aka Lunati A3.

I KNOW what the cam designer would tell you.
 

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Discussion Starter · #10 ·
Finally was able to reach Lunati. They agreed with the general consensus. Leave it at 104.5. He even said that the designer would have me advance it as much as I could. Seems I heard that somewhere.
 
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