Don Terrill’s Speed-Talk

You probabily also did not actually measure the piston dome
true volume.

Milling the heads reduces vtp clearance.

You can also consider a custom thickness head gasket to max cr while still keeping piston to deck clearance @tdc sufficient. If the pistons are below deck there is room to play here.

You should have bought a cam that is speced-designed
with the low cr in mind. (special closing side)
You can see the effect by testing at various lash and cam phasing +/-.

In thin air you'd want to max the tuned runner inertial ram effect of the tunnel ram..

(extra large carb capacity, correct valve timing, max use of hood scoop flow aid, )

Interesting experience looking for tunnel ram carbs. I've emailed all the big carb shops to get a price and see what they recomend for my combo

Chuck Nuyetten
CSU
Braswell
Pro systems
CFM
AED

maybe more that i can't remember.

Most suggest around 800 - 850 cfm carbs up to dual 1050 dominators. Prices have ranged from $1380 pair to $3400 for the dominators (race only).
I can also buy QFT tunnel ram carbs for about $1700 canadian dollars for a pair. They are calibrated for a TR but not custom built to my app.
I know there is cheaper ways to do it but i'd like to start with something in the ball park for tuning and not leave to much power on the table.

I seem to recall F-bird telling me not to waste money on fancy carbs.
Today i learned the difference between a regular quick fuel carb and a dedicated quick fuel tunnel ram carb. Pay attention :

regular carb # Q-850
$749.95
has jet extensions.

tunnel ram carb #Q-850-2
$799.95
does not have jet extensions.

i learned this straight from holley. This doesn't mean that carbs from other builders are the same.

I think this is what i have decided on:
https://www.holley.com/products/fuel_sy ... /0-67200BK
Brian

From what I have seen over the years is that T Ram carbs are metered different from single carbs due to the fact that you are dealing with twice the air and fuel.

Call QF and I bet you find out more!

Now did you ask QF why those TR carbs dont have jet extensions and are more expensive???
Are you hoping the holley/s you linked will go straight on the TR and work fine??

For your application I would do 2 750's. I have ran tunnel rams and Holleys since 1982 and they are very user friendly.

The QFT carbs don't have jet extensions because they are meant to mount sideways. I expect to have to fine tune any carb i buy. If you look at the spec sheet on the QFT carbs, all the jets and bleeds are also exactly the same.

thanks old school. I think you are right.

one more track day coming up. Here is a picture from my last race

That is a smooth car.

I like the 750's you chose. Good play. I like the purple metering blocks ha ha .

GARY C wrote:From what I have seen over the years is that T Ram carbs are metered different from single carbs due to the fact that you are dealing with twice the air and fuel.

Call QF and I bet you find out more!

You never double the airflow through 2 carbs.

You double the jet area, double the needle and seat area and also double the emulsion and air bleed area.

If someone is telling you up the difference between a single 4 tune up and a TR is some jet extensions...well common sense should tell you that is incorrect.

prairiehotrodder wrote:The QFT carbs don't have jet extensions because they are meant to mount sideways. I expect to have to fine tune any carb i buy. If you look at the spec sheet on the QFT carbs, all the jets and bleeds are also exactly the same.

Yes this is what im getting at, TR (sideways ) carbs dont need extensions, and if the jet/bleed spec is the same then what is it about them that they are charging more $for? Did you ask?

i asked what the difference is. He said the jet extensions. I asked if i could just remove them and save the $50 and have the same carb. He said "pretty much".

Thats all he told me. Maybe he didn't know either and maybe i should have asked more questions. I'll leave it alone. I'm gonna take an educated guess that if there is a difference it is in the emulsion jets (is that the ones in a vertical row on the metering block?) Because the QFT wesite says the MJ and the PV and the Air bleeds are the same.
brian

prairiehotrodder wrote:i asked what the difference is. He said the jet extensions. I asked if i could just remove them and save the $50 and have the same carb. He said "pretty much".

Thats all he told me. Maybe he didn't know either and maybe i should have asked more questions. I'll leave it alone. I'm gonna take an educated guess that if there is a difference it is in the emulsion jets (is that the ones in a vertical row on the metering block?) Because the QFT wesite says the MJ and the PV and the Air bleeds are the same.
brian

Yes correct on emulsion jets, vertical row in metering block.

Given that the G forces are 90° to 'normal' for a sideways drag carb, do they use circle track-type cutaway floats?