Hot Rod Forum banner

1 - 15 of 15 Posts

·
Registered SBC Addict
Joined
·
897 Posts
Discussion Starter #1
hey yall
a friend wants to put a cheap big cap HEI in the 71 chevy 250 6cyl, car if it makes a difference..

will this work? even tho they say it wont fit a 71?? just a 75-76..
https://www.summitracing.com/parts/sgt-gm34/overview/year/1971/make/chevrolet/model/el-camino
.
whats the difference in these?? besides the price/quality??
https://www.summitracing.com/search...6+4294949232+4294944557+4294944556+4294944551
.
and another Q
is there a even/odd fire strait 6?? 230, 250 or 292??

some reason I cant get the search to work?? it just says loading..

thanks in advance JJ
 

·
Registered SBC Addict
Joined
·
897 Posts
Discussion Starter #3
thank you Joe

I haven't touched a 6cyl in forever..
is there a difference in a I6 and a L6 250??

yea I was talking about the search on Hotroders
I just get a black screen, says loading, and nothing ever happens..

thanks
 

·
More for Less Racer
Joined
·
19,899 Posts
The difference between the two links you posted is the first is just a stock replacement for the 1975-76 Emissions calibrated piece. Stock coil, most likely stock slow mechanical advance curve with a large amount of degrees added by the mechanism(26-30°) and intended for low stock initial timing settings, likely stock type non-adjustable vacuum advance with a large 12-20 degree travel.

The more expensive second one you linked, such as the Summit Blueprint has a higher output coil, probably a better module to match, a more performance oriented mechanical advance curve and a much shorter performance oriented vacuum advance set-up.

Both can be retro fit into the 1971 engine....the "does not fit" deal they are posting is for stock-to-stock replacement,,,,1971 stock is points, so that is why they say it doesn't "fit".

You'll find in the hotrodder world, you often have to be smarter and more informed than the parts counter kid or online store/search engine. ;)
 

·
Registered SBC Addict
Joined
·
897 Posts
Discussion Starter #6
thanks Eric and Joe

that's exactly what I wanted to hear,
not a lot of changes from year to year on the I6s I guess..

yes I understand the stock slow mechanical advance curves,
this is just a bone stock motor he wants to get it runnin..

hey i was that parts counter kid about 45yrs ago,
at the local mom and pop parts store, workin on peoples cars out in the driveway..
I kept up on the SBCs for a long time, just haven even seen a I6 in years,
we just pulled them and put'em in the corner with all the abused 305s lol..

yall have a idea/ruff guess what the total timing would be on the stock 250??
thanks
 

·
More for Less Racer
Joined
·
19,899 Posts
I don't know what the total mechanical timing would be on the L6....my experience is the same as yours....make it run and drive it for a bit, just until the V8 replacement for the boat anchor under the hood is done, then the 6 either went to scrap, or if it was a decent piece got sold to the first taker.

Don't forget the resistor wire/ballast resistor that fed the stock points coil needs to be removed and replaced or bypassed to get a full 12V to the HEI.
 

·
Registered SBC Addict
Joined
·
897 Posts
Discussion Starter #8
thanks Eric

x2 on the resistor wire, someone has already shortened it, so it gets low 12v,
we'll fix that so the hei gets the full voltage..
 

·
Registered
Joined
·
4,303 Posts
Eric mentioned the stock unit has a timing curve setup for a stock engine. If your/your friend's engine is mostly stock, then the stock timing curve works pretty well - at least in my experience. I tried jumping the initial a bunch and limiting the mechanical on a mild 250 and it was a better driver with more 'stockish' curve. IIRC adding only 5-6 degrees of initial and limiting the mechanical by 3-4 worked out well for most driving conditions.

At the time I found a junkyard loaded with L6's and grabbed 3 dizzies. Added a new cap, rotor and drive gear - been on that motor for almost 7 years now. The joy of the stock HEI - reliability.

Good luck.
 

·
Registered SBC Addict
Joined
·
897 Posts
Discussion Starter #13
thanks 64NH
I was going to tell him to start a 10*BTDC and see how much he gets from the vac adv..
I see specs from 0* std to 4*BTDC auto, and 4*-8* for later yrs I guess??

X2 on the HEI reliability, with a good spare module in the glove box.. lol
 

·
Registered
Joined
·
5,556 Posts
For the price of the skip white dizzy, I carried a spare one instead of a module. Easier to swap the whole thing.
My last two six bangers in a 65 c10 and 67 gmc I ran 14 initial and left the curve alone in the dizzy. Never had a problem.
 
1 - 15 of 15 Posts
Top