1980 HD trike, 1993 4.3 2Bbl, HEI with vacuum advance,1972 350THM, 1969 chevy 309 pumpkin...i need old skool help...advise...jus built this trike and trying to understand setting up timing VIA: TBI/ECU & Carb/HEI..i see vids on youtube but not what im looking for:
1985-87 4.3 4Bbl setups with HEI states initial timing at 4 degrees BTDC,,,
so i go with 4 and it but runs a lil hot and got 14 MPG..
i go with 2 BTDC and it runs and not so hot and got 18 MPG.an ok heat,,and i think i can live with this setting,,as you can see in the pic...i cant hear $hip due to exhaust crammed in my ears
Should i go with TDC? since the 93 TBI was setup on TDC controlled by ECU...
What would you gap the plugs at?
enjoy pics

 

4.3 is just a 350 v8 minus 2 Cylinders. Just do the good old performance timing setup for SBC. Recurve distributor for 22 degrees of centrifugal advance, all in by 3000 rpm. Then set timing to 34 degrees at 3000 rpm with vacuum advance unplugged. Initial timing falls where it may but should be around 12 degrees. 12 + 22 = 34. Plug vacuum advance into manifold vacuum and timing at idle should be around 12 + 14 = 26. With vacuum advance plugged in, max timing of 12 + 22+ 14 = 48 degrees. See how that works? Dont try to set timing at any rpm except 3000 or above 36 degrees for any reason. Good luck!!

 

“””””Recurve distributor for 22 degrees of centrifugal advance, all in by 3000 rpm“””” how do I do this???

 

Buy any number of performance advance curve kits (with weights) for HEI distributor. If more than 22 degrees, you can limit the advance. This is assuming you have the big cap HEI distributor.

If you don't have a big-cap HEI distributor already, get you something like this + an advance curve kit.

 

i do have that set up

 

Then all you need is the advance curve kit. Is it a stock distributor or aftermarket "performance piece"? If aftermarket it may already be close and you can check the advance curve to see if it will be OK as is.

Retarded timing will make an engine run hot. I think yours is probably this way. Also performance is way down with retarded timing. I assume this is a stock 4.3 as far as pistons, heads, and cam?

Note that 1993 did not have a carburetor like you claim. So what do you have? Ok do see a vacuum advance in second photo. Just need to confirm what carb and distributor is being used. Close photos please.