Thermoquad vs Quadrajet

GTX JOHN · 12-15-2009, 04:15 PM

My Stock Dodge Truck (N/SA) can run either a small (1 and 3/8 ) Thermoquad or a quadrajet. I never used a Quadrajet since I race mopars. Is it any faster, I know It couldn't be much harder to figure out? Are the Edelbrock carbs preferable?

Thanks John Irving

George Mirza · 12-15-2009, 08:06 PM

It would be interesting to see which one is faster. At least you can buy a new quadrajet, not a 30 year old TQ that might be good.
I bet a few SS racers have been there already and can tell you which is better. The mid 80's 318 combo is pretty good in SS and I think you can run either carb on it depending on year claimed.

GTX JOHN · 12-15-2009, 08:40 PM

The 318 engine in superstock is rated 4 more HP with a Quadrajet than
Thermoquad I didn't know you could buy a quadrajet new. I know jet sell a race carb but I didn't know if was a new unit or rebuilt. Does anybody know if the are usable(Jet Race Model) out of box. Who can I pay to rework one on West Coast that is compentent? Thanks

GTX JOHN · 12-15-2009, 08:48 PM

The 318 SS is four more HP with Quad but it still seems more popular. Same HP on 360 Truck. Didn't know you could buy either one new anymore. Jet sell a Quad the state is Stock/SS ready but I thought it was rebuilt not new. Does anybody know if they work? Any reccomendations on who to have build me one on West Coast? Thanks

SORRY Didn't mean to post twice in a row

Todd Boyer · 12-15-2009, 10:45 PM

I haven't heard his name in quite some time, but isn't Val Hedworth a good Q-Jet man? Not sure on this John as I'm a Mopar man myself. I also believe Ken Etter runs a Q-Jet on his 318 SS Shadow.

Todd Boyer · 12-15-2009, 10:47 PM

I also believe Greg Gay runs, or at least can run, both carbs on his 318 SS Mirada, but not sure who does his carbs.

Philip Saran · 12-15-2009, 11:10 PM

GTX John,

Give Bob Mazzolini a call at his shop. I believe he ran the QJ on both of his
old SSGT cars that are now owned by Wayne Taylor and Bill Riddle, also talk
with Ken Etter about this.

Danny Ashley · 12-17-2009, 07:22 PM

John:
My earlier post was based on your Q-Jet being an 800CFM . I was told by a Mopar guy that Thermoquads came only in 800 and 1000 CFM's but according to Mr. Wahl, there's a 750. That being the case, you could use an Edelbrock #1901 or # 1902. I'd better stick to giving advise just on Q-Jets.LOL. I would check with NHRA to make sure what Quadrajet is legal before spending any money. Danny

Jeff Lee · 12-17-2009, 07:28 PM

I was under the impression all Q-Jets were 750 CFM except those with only one ring around the booster which were 800 CFM. The 800 was a specialty carb as used on 455 HO Pontiac, SD 455 and probably a few others. Correct or wrong?

On the T-Quad, it's 750, 800 & 1000. Basically small block, big block and motor home big block. Again, correct or wrong? Wasn't there a red bowl race T-Quad @ 1100 or 1200 CFM?

Danny Ashley · 12-17-2009, 10:02 PM

Jeff:
All Q-Jets were 750CFM (1.093 venturi) until 1971 when the 800's (1.218 venturi) were installed on Buicks. Pontiac got their's in 1973, Olds 1975, and Chevy also 1975. Not sure about Caddy's. The single booster were on Pontiacs in 1971. I have heard that they were on a few late 1970 and early 1972's. The 7041263 was used on low performance 400's and I think 455's. These carburetors venturi measures 1.093. I had one flowed and was told it flowed inbetween a 750 and a 800. The Pontiac community always refer to these as an 800. Is there an advantage to these over an 750? NHRA thinks so because they say they are only legal on the engines they came on. Danny

12-15-2009, 08:06 PM	#2
George Mirza Senior Member Join Date: Jan 2002 Location: North Attleborough Ma. Posts: 522 Likes: 0 Liked 0 Times in 0 Posts	Re: Thermoquad vs Quadrajet It would be interesting to see which one is faster. At least you can buy a new quadrajet, not a 30 year old TQ that might be good. I bet a few SS racers have been there already and can tell you which is better. The mid 80's 318 combo is pretty good in SS and I think you can run either carb on it depending on year claimed.

12-15-2009, 08:40 PM	#3
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,737 Likes: 2,813 Liked 2,489 Times in 699 Posts	Re: Thermoquad vs Quadrajet The 318 engine in superstock is rated 4 more HP with a Quadrajet than Thermoquad I didn't know you could buy a quadrajet new. I know jet sell a race carb but I didn't know if was a new unit or rebuilt. Does anybody know if the are usable(Jet Race Model) out of box. Who can I pay to rework one on West Coast that is compentent? Thanks

12-15-2009, 08:48 PM	#4
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,737 Likes: 2,813 Liked 2,489 Times in 699 Posts	Re: Thermoquad vs Quadrajet The 318 SS is four more HP with Quad but it still seems more popular. Same HP on 360 Truck. Didn't know you could buy either one new anymore. Jet sell a Quad the state is Stock/SS ready but I thought it was rebuilt not new. Does anybody know if they work? Any reccomendations on who to have build me one on West Coast? Thanks SORRY Didn't mean to post twice in a row Last edited by GTX JOHN; 12-15-2009 at 10:30 PM.

12-15-2009, 10:45 PM	#5
Todd Boyer Senior Member Join Date: Feb 2004 Location: Saint John NB Canada Posts: 561 Likes: 30 Liked 6 Times in 5 Posts	Re: Thermoquad vs Quadrajet I haven't heard his name in quite some time, but isn't Val Hedworth a good Q-Jet man? Not sure on this John as I'm a Mopar man myself. I also believe Ken Etter runs a Q-Jet on his 318 SS Shadow.

12-15-2009, 10:47 PM	#6
Todd Boyer Senior Member Join Date: Feb 2004 Location: Saint John NB Canada Posts: 561 Likes: 30 Liked 6 Times in 5 Posts	Re: Thermoquad vs Quadrajet I also believe Greg Gay runs, or at least can run, both carbs on his 318 SS Mirada, but not sure who does his carbs.

12-15-2009, 04:15 PM	#1
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,737 Likes: 2,813 Liked 2,489 Times in 699 Posts	Thermoquad vs Quadrajet My Stock Dodge Truck (N/SA) can run either a small (1 and 3/8 ) Thermoquad or a quadrajet. I never used a Quadrajet since I race mopars. Is it any faster, I know It couldn't be much harder to figure out? Are the Edelbrock carbs preferable? Thanks John Irving

12-15-2009, 11:10 PM	#7
Philip Saran Senior Member Join Date: Oct 2006 Location: Parker, CO. Posts: 728 Likes: 168 Liked 14 Times in 11 Posts	Re: Thermoquad vs Quadrajet GTX John, Give Bob Mazzolini a call at his shop. I believe he ran the QJ on both of his old SSGT cars that are now owned by Wayne Taylor and Bill Riddle, also talk with Ken Etter about this. __________________ Phil Saran Parker, Colorado

12-17-2009, 07:22 PM	#8
Danny Ashley Member Join Date: Nov 2001 Location: Marion,In. Posts: 267 Likes: 60 Liked 110 Times in 29 Posts	Re: Thermoquad vs Quadrajet John: My earlier post was based on your Q-Jet being an 800CFM . I was told by a Mopar guy that Thermoquads came only in 800 and 1000 CFM's but according to Mr. Wahl, there's a 750. That being the case, you could use an Edelbrock #1901 or # 1902. I'd better stick to giving advise just on Q-Jets.LOL. I would check with NHRA to make sure what Quadrajet is legal before spending any money. Danny

12-17-2009, 07:28 PM	#9
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Thermoquad vs Quadrajet I was under the impression all Q-Jets were 750 CFM except those with only one ring around the booster which were 800 CFM. The 800 was a specialty carb as used on 455 HO Pontiac, SD 455 and probably a few others. Correct or wrong? On the T-Quad, it's 750, 800 & 1000. Basically small block, big block and motor home big block. Again, correct or wrong? Wasn't there a red bowl race T-Quad @ 1100 or 1200 CFM? __________________ Jeff Lee 7494 D/S '70 AMX

12-17-2009, 10:02 PM	#10
Danny Ashley Member Join Date: Nov 2001 Location: Marion,In. Posts: 267 Likes: 60 Liked 110 Times in 29 Posts	Re: Thermoquad vs Quadrajet Jeff: All Q-Jets were 750CFM (1.093 venturi) until 1971 when the 800's (1.218 venturi) were installed on Buicks. Pontiac got their's in 1973, Olds 1975, and Chevy also 1975. Not sure about Caddy's. The single booster were on Pontiacs in 1971. I have heard that they were on a few late 1970 and early 1972's. The 7041263 was used on low performance 400's and I think 455's. These carburetors venturi measures 1.093. I had one flowed and was told it flowed inbetween a 750 and a 800. The Pontiac community always refer to these as an 800. Is there an advantage to these over an 750? NHRA thinks so because they say they are only legal on the engines they came on. Danny