[68hotbird]

461 12:1 compression edelbrock 72cc 320 cfm heads 276/280 solid roller. currently at 36 degrees locked. thinking about trying 38 and 40 just wondering if anyone has any experience before I get to test and tune Friday weather permitting

[ponjohn]

CNC chamber?

[Jack Ferris]

For the standard chamber that’s about right. The heart shaped version can be less.

[68hotbird]

non cnc chambers

[Mike S]

I have a 468 12-1 comp. standard chambered e-heads. I use VP c-12 for fuel. My car ran fastest at 40. I keep it at 38.

[Scott Roberts]

Originally Posted by Mike S

I have a 468 12-1 comp. standard chambered e-heads. I use VP c-12 for fuel. My car ran fastest at 40. I keep it at 38.

At 40??? That says it's not an efficient chamber... kind I
Of like a sbc.....

[charlie66]

My 11.3 to 1 E head made peak power at 35 degrees

[Dragncar]

How much power are you leaving on the table between old E heads with wedge chamber vs their new ones with LS chamber ? Same everything, CR all that.
Has anyone found out for sure ?

[Hooter]

I ran 36 in both of my motors with the conventional chamber e heads.

[AG]

38 degrees locked with old style chamber 72 cc heads, 11.2 CR.

[mysticmissle]

i run about 35 on my dinosuar chamber eheads. curious what you guys may have found et wise rasiing the 2-5 degrees over 35?

[73 TRANSAM]

When I was at the engine dyno, it made the most power NA at 37 degrees but this is a turbo application setup. After the NA pull, we switched over to turbo setup.

[charlie66]

I tried the timing lower and higher on the dyno and at the track. Went the fastast at the track with 35 and made the most power on the dyno with 35 degrees..

[BB70]

Old style chamber, 10.7, 93 pump gas- I ran at 35, 38 briefly, but took it down to 32.5 or so. Reason being I didn't like the look of the upper shell on the rod bearings last time it was apart. Never heard anything, but that doesn't mean anything. I'm probably leaving some power on the table, but it runs pretty strong.

[Skip Fix]

38 seem to be what both of mine like on the dyno and track.

[68hotbird]

looks like 38 was the best number for et and mph at the track last night

[hgerhardt]

My 72cc E-heads are on a 434 (428) with solid roller of 248-254 @.050, 11.4:1 compression, and makes best power at 30 deg.

When I first installed the heads, I ran 36 deg which the previous 87cc heads liked, but during tuning on the strip figured out it now likes much less timing, which to me says the chambers are pretty efficient. Also decked the block with pistons at zero, so having efficient quench might have something to do with needing less timing too.

[blueghoast]

My 72-cc chamb heads standard chamb likes 38.
Tried more and less, 38 was the best performance
That was on two different motor 1 12.1
And one10.65.1 38*

GT.

[AIR RAM]

I ran 36 degrees with the 72cc EDL heads on my 10.5:1 350... it ran 13.8 @ 108 with lots of tire spin (Peg leg)

SPEED SAFE, NICK

[steve25]

There's no blanket magic number for what total timing your should run for the greatest peak hp numbers.

If you need to ask then your not at a test and tune track day finding out what your combo wants.

Most every motor is different, and the motors compression ratio and how fast the motors cylinder pressure rises are key factors in the timing needs.

Cylinder pressure rise rate is directly related to the Cam you are running and the total timing that works for a roller Cam race motor with well over 250 duration @.050" will not be what works best for a hydro roller street motor with a duration of 230 duration @.050".