Timing

[ChevyGearHeads]

Hello Everyone!

I have a crate LM1 350 with a Crane .500/.500 cam, Summit 15123 heads and an Edelbrock Torker with a Edelbrok 1405. Distributor is a DUI with a stock vacuum advance.

Wondering where to set the timing?

Any ideas very much appreciated.

[geezer#99]

That’s a lot of cam for low compression.
Read this.

https://www.badasscars.com/index.cfm...&product_id=76

[AussieinNC]

12 degrees BTDC at idle

All in 36 degrees BTDC at 3500 rpm

That is a lot of cam for what is essentially a 9:1 compression motor...the heads you put on are 72 cc against 75 cc factory...not really enough to make a difference...

What is this engine going into?
Transmission?
Rear gear?

[Ziegelsteinfaust]

20 some years ago CarCraft magazine did a couple of articles called agent 87.

Well they took a low compression sbc, and put the manifold vacuum to the vacuum advance on the distributor. This kept the engine easy to start, but put a good bit of power down under the curve. Compared to a normally set up combo.

I have done it a couple of times on vehicles I got with good running stock engines. The engine will have a tendency to surge in gear, but the extra torque is nice.

For low compression engines I like about 14-16* initial timing, and about 36* all in. A simple weight kit for 10 bucks works wonders.

[geezer#99]

Originally Posted by Ziegelsteinfaust

20 some years ago CarCraft magazine did a couple of articles called agent 87.

Well they took a low compression sbc, and put the manifold vacuum to the vacuum advance on the distributor. This kept the engine easy to start, but put a good bit of power down under the curve. Compared to a normally set up combo.

I have done it a couple of times on vehicles I got with good running stock engines. The engine will have a tendency to surge in gear, but the extra torque is nice.

For low compression engines I like about 14-16* initial timing, and about 36* all in. A simple weight kit for 10 bucks works wonders.

Good to excellent timing numbers!
To control the surge just limit the vac advance amount to 10-12 degrees.

[68 P.O.S.]

GM engineers found years ago SBCs run best at ~36 btdc total timing. Total timing is more important to set than initial. Set your total to 36 and then check where your inital lands for reference. Also, follow the directions from DUI to setup your distributor correctly.

[Ziegelsteinfaust]

Forgot sometimes you have to increase total timing increase.

Alot of distributors have 18* total advance, but they are easy to increase to 20-22*.