1970 Lt1 carb. settings

[70 Forest Green Zee]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: al8apex</div><div class="ubbcode-body">OEM stock were 72 primary and 76 secondary, they were way to rich for the 1100 feet elevation here in Phoenix ...

the above may work ok for a drag car but will be &quot;phat&quot; for the street

again, IMHO, YMMV, etc </div></div>

Jim...according to Eric the stock jet size is 70 primary and 76 secondary...power valve is 6.5. I have the 4489 carb for NA9 Calf emissions and I don't know if they used different jet sizes than a non NA9 carb. A friend of mine has a 69Z and his non NA9 carb is also jetted 70 and 76 with 6.5 power valves.

[YENKO DEUCE REGISTRY]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: todd micheal</div><div class="ubbcode-body">Marlin, forgive me but how do i set accelerator pump a w.o.t. ( hold open and should have .015 gap) What does old stlye spring look like for accelerator pump? with no lock nut. And what is the best way to block off p.v. in secondary? What number ngk's And i do have a dial in timing light. thank you for all the help. TODD </div></div>

Running the 82's on the secondary side with a blocked p/v is indeed on the fat side, but it rocks! The AC plugs will foul (quicker than normal) with this setup, but NGK's will hold out a bit longer. I have 2 sets of NGK's, and just swap out, clean up, swap out, etc... Did I mention that this setup RIPS [img]<<GRAEMLIN_URL>>/grin.gif[/img] especially in 3 gear!!

Todd, the Acc setting for wot would indeed be with the linkage at wot, a feeler guage will do it. I believe (others correct me if I'm wrong) that the 'at rest' gap is more important, as it will help prevent a stumble. The old spring - not sure what a new-age one looks like! Just make sure its not something funky, no funky nuts either (no comments from the midwest gallery!). You need to buy a 'blocked' p/v for the secondary, you don't have to do anything to block one, just install it. You need a set of part number XR5 for the plugs, don't bother with the fancy, higher priced NGK's, just use the basic version = XR5.

Oh, btw = get the timing right, by that I mean, set up the carb per the above, and then set the timing - then test drive it, adjust it - then test it. That is the best way to dial in the timing, I usually take a wrench and the light with me and just pull over in a parking lot, tweak it, and then blast off [img]<<GRAEMLIN_URL>>/wink.gif[/img]

[al8apex]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 70 Forest Green Zee</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: al8apex</div><div class="ubbcode-body">OEM stock were 72 primary and 76 secondary, they were way to rich for the 1100 feet elevation here in Phoenix ...

the above may work ok for a drag car but will be &quot;phat&quot; for the street

again, IMHO, YMMV, etc </div></div>

Jim...according to Eric the stock jet size is 70 primary and 76 secondary...power valve is 6.5. I have the 4489 carb for NA9 Calf emissions and I don't know if they used different jet sizes than a non NA9 carb. A friend of mine has a 69Z and his non NA9 carb is also jetted 70 and 76 with 6.5 power valves. </div></div>

my bad, I had stated it correctly earlier in this thread, 70 &amp; 76 were OEM, according to the link I posted earlier in this thread, sorry.

[70 Forest Green Zee]

No problem Jim...you're right on 99.9% of the time! [img]<<GRAEMLIN_URL>>/beers.gif[/img]

[YENKO DEUCE REGISTRY]

Actually, the 70 or 72 primary jets are too fat for the street here in PA too. In street trim I put 68's in the primary side to help stave off the plug fouling, but I leave the 82's and the blocked p/v in the secondary side. I've got the timing curve and secondary spring synced up to the point that just when the full timing advance is coming in - so is the slam from the blocked p/v and the fat jets. This makes 2nd and 3rd gears a blast to drive! [img]<<GRAEMLIN_URL>>/grin.gif[/img]

[todd micheal]

Marlin, What do you think about a 50cc accerlator pump??Should i give a shot, and down size squirter little??? any one else many chime in. Thanks for all the help out there, Todd

[al8apex]

a 50cc pump will just drown the engine, he has too much fuel it sounds like and not enough timing

[YENKO DEUCE REGISTRY]

No.