Correct timing setting for a 1970 350 (9.1:1 w/ HEI)

[BillyTungsten]

Engine is running (after swap) but I get a wicked backfire coming off the throttle and overall power is lower than it should be. I bought a timing light yesterday, but have never timed an engine.

Anyone know where I should be from TDC? Any other general advice on correct timing is also appreciated!

 

[unclematty]

need some more info from your end, what cam are you running, carbed or tbi or tpi, egr or not, I'll get back to you as soon as I see info

 

[3 on the tree]

I would start at 8 degrees BEFORE TDC, as a baseline. Don't forget to unhook and plug your vac advance line while setting the timing.

 

[BillyTungsten]

more info & pics...

The engine is from my 1973 blazer, PO told me it was a 1970 350. I do not believe the cam is anything but stock, as the PO had a pretty flowery list of anything that wasn't stock.

It is carburated


One of those hoses is the vac advance that I need to plug, right?

Also, this is what the timing mark looks like...

which is 'before' versus 'after' to the left of the mark or the right as I face the engine?

Thanks! I am learning thanks to you guys!

 

[SUBFAN]

See the pot on the distributer under/behind the fuel inlet on the carb? That is the vacuum advance. Simply pull that hose off, and plug it.

On the timing mark, to the right of 0 is the advance side, I do believe. (Been awhile)

Although looking at it, I think the A stands for advance, and the R stands for retarded....

 

[BillyTungsten]

TTT...

I am waiting for some info so I can get this done... I don't want to put the PS pump in until it is timed, so I am kind off hung up until someone helps with timing info.

 

[SUBFAN]

Put that PS pump on there, you can still time it with it in place....