yer 4 barrel spread bore

vac seconds

The Carter Thermoquad carby was and still is a very underrated Carb
I beleive from memory they were rated to 725CFM

I have the original service/tuning leaflet for this Carb from Ford detailing how to set the gaps and bend the linkages ... when i purchased my XC many years ago it was getting 9 MPG...

after tuningit properly... it was getting 31 MPG

this carb is better than the holley because it has small primaries (for cruising) and VERY Large Secondaries (comparitively speaking)

turn an equivalent Holly upside down and have a look at the Carter Thermoquad upside down... you'll see what i mean

Yeah, we have a thermoquad on our 351 in our Speedway Car, and bloody hell, when you put the foot down and those secondaries open up you can bloody feel it lol. Only prob is keepin the power down to the track when the track is a lil wet, but when it dries out goes like a shower of s**t.

a good alternative to a thermoquad carby is the edlebrock carby. They are easy to tune and you could do it yourself if you get the manual as it gives you the size needle and jet you need to richen or lean it up.
I have one on my boat and with the needles and jet all I done was email edlebrock in the states and said what I needed and they posted them out to me free of charge. Can't argue with their customer service.

On my old xc (wish I still had it) worked 302 first carb setup was edelbrock performer manifold with an aray of holley carbs from 600vac to 750dp and every thing in between. The best setup I found was a bet that I lost. Setup was stock xe four barrel manifold with xd thermoquad 780cfm spread bore carb, ripped the ratchet clean out of the reclining drivers seat more than once while holding on to the steering wheel. Only problem was a flat spot at low revs when punched with full throttle.

Sorry it was 850 cfm carb not 780cfm

bloody hell thermoquads are the s**t! u could almost get ya hand sucked down those secondaries ....ahh memories