DRILLING OUT 2BBL JETS
- Thread starter A/MP
- Start date
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Acquire a bunch of extra jets and drive the in two or three thou increments.
Probably will need to drill throttle blades to get it to idle clean with a Stock
Elim. camshaft.
If you are running a 78 up 318 combo where it is legal
you will be much happier with a Thermoquad stocker.
Probably will need to drill throttle blades to get it to idle clean with a Stock
Elim. camshaft.
If you are running a 78 up 318 combo where it is legal
you will be much happier with a Thermoquad stocker.
More information needed, please.
True but the 2 Brl is very low flow and rated too
much HP by NHRA. The Thermoquad has great flow
and a reasonable HP rating.
I have raced this combo for 20 years+, and both my coupe and wagon
have held National Records in M/SA N/SA O/SA and won their class at Indy
with the 4 Brl.
Well, despite extensive testing the 2 brl., was never very competitive.
If you love 2 Brls. the 273 is a better deal.
MY .02 = For free!
much HP by NHRA. The Thermoquad has great flow
and a reasonable HP rating.
I have raced this combo for 20 years+, and both my coupe and wagon
have held National Records in M/SA N/SA O/SA and won their class at Indy
with the 4 Brl.
Well, despite extensive testing the 2 brl., was never very competitive.
If you love 2 Brls. the 273 is a better deal.
MY .02 = For free!
The engine is my 318 Aspen N/SA has over a 1000 passes
on it last 15 years. Heads have been touched up a couple
times and that is all.
Let me know if you need any help or advise!
on it last 15 years. Heads have been touched up a couple
times and that is all.
Let me know if you need any help or advise!
BSB67
Well-Known Member
Your putting together a Stock Eliminator race car and want a 2bbl verses a 4bbl for maintenance reasons?
The last couple races the Wagon. 80 to .90 under with 20/50 Oil
and very little timing plus 100+ lbs. overweight to avoid getting
HP adjustments. A Two barrel 318 Stocker has never run anything at all
close to that performance ever to my knowledge. Just no CFM to
work with at all. I can run the 850 big Thermoquad legally on the
wagon. If you put the two barrel on a four barrel flow bench (less
inches of mercury), I doubt that you would ever get 300 CFM of flow out
of it comparing Apples to Apples on a four barrel bench with the two barrel.
Drilling out the jets changes the mixture but does not increase Air Flow
any.
My .02 = For Free!
and very little timing plus 100+ lbs. overweight to avoid getting
HP adjustments. A Two barrel 318 Stocker has never run anything at all
close to that performance ever to my knowledge. Just no CFM to
work with at all. I can run the 850 big Thermoquad legally on the
wagon. If you put the two barrel on a four barrel flow bench (less
inches of mercury), I doubt that you would ever get 300 CFM of flow out
of it comparing Apples to Apples on a four barrel bench with the two barrel.
Drilling out the jets changes the mixture but does not increase Air Flow
any.
My .02 = For Free!
mikedevore
Well-Known Member
John, whats your thoughts on the 2bbl holley 360 combo?
That is a nearly impossible combo to run competitive
in Stock. It is rated at 245HP and would need to be
well under 200HP to be competitive.
The carb is way too small to support the HP needed to be competitive
in Stock or SS. You would need to generate 370HP in stock
or 490HP in SS to be in the middle of the pack.
We have experimented and spent money with the 318 2 Brl.
which was dropped to 185HP years ago by NHRA.
We tried different camshafts and headers among other changes
and never could get it to run anywhere near competitively even at that power
level rating.
The Thermoquad is an amazing carb. for Drag Racing and no reason not to run
it. We have work arounds for most of the other challenges in Stock/SS but
CFM Air flow is critical.
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Don't one or two years of the 273 have a larger CFM carb.
Maybe around 65?
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