Thermoquad vs Quadrajet

Dragsinger · 12-16-2009, 06:01 AM

Also consider talking with Danny Ashley. He post here and is an accomplished Q-jet builder.

njk53 · 12-16-2009, 10:48 AM

Speak to Dean Oliver (870) 830-5470. Excellent and knowledgable Q-Jet builder and an easy person to talk to.

Danny Ashley · 12-16-2009, 12:08 PM

Larry,
Thanks for the plug. Your new car looks great!

John,
I'v never heard of anyone comparing the Q-Jet with a Thermoquad so here's my opinion. Since both are rated at 800 cfm and if you had both properly jetted, it should be a wash. The engine doesn't know type just flow. You would have to compare a known good Q-Jet with a known good Thermoquad to know for sure. I assume that in the Thermoquad world as in the Q-Jet's, there is sometimes a big difference between cores. You could do up 5 of the same number and one would probably be faster. Dynos won't tell you either. The real test is the time slip. Period. If you choose to go with an Edelbrock, there are 4 numbers you can use; #1903, 1904, 1910, and 1905. The 1910 claimes to be an 850 but the primaries measure 1.218 which is what a 800 is. The 1905 is a direct replacement fot the Thermoquad on 1985 and earlier engines so it will have the correct linkage for Mopar engines. The Edelbrock are no longer manufactured and only occasionally will you find a new one from a parts supplier. E-Bay is a good source for used ones and sometimes there are new ones on there also. 800 cfm Quadrajets were used on a wide variety of GM engines from 301 to 455 in Buick, Olds, Pontiac, Cadilliac, and Chevy so if you know what to look for they can be found on E-Bay also. I stock new and used 800's. Don't be afraid to have someone outside California blueprint a Q-Jet for you as ther are a lot of good builders out there. Some of my Calif. customers include Grossi, DeFrank, Glassbrenner, Tim Smith, Bob Aceves, Bob Mulrey,and Ed Drucker . I'm not suppose to advertise on here so if you need my number maybe someone will post it or you can PM me. Danny

Jeff Lee · 12-16-2009, 06:32 PM

I need a Q-Jet # 7040263 - 1970 Pontiac 49 state manual trans core. 1970 date, no superseded date code.
Please email direct
JeffLeeAzRealty@qwest.net

Danny Ashley · 12-16-2009, 08:34 PM

Jeff;
Go to customrebuiltcarbs.com. They're showing 7 in stock. Click on classic carbs, then Pontiac, then follow the charts. Danny

Jeff Lee · 12-16-2009, 11:48 PM

Thanks, I sent in a request for price quote. I know it's a bendover part, how bad do you think it will be?

Jim Wahl · 12-17-2009, 01:51 PM

Remember, no matter which carb you choose, the primary and secondaries must be the same size as the original OEM carb. The 1 3/8 primary Thermoquad is actually rated at 750, where the 1 1/2 primary is rated at 800. Jim

12-16-2009, 10:48 AM	#2
njk53 Senior Member Join Date: Jul 2007 Location: East China, MI Posts: 504 Likes: 0 Liked 0 Times in 0 Posts	Re: Thermoquad vs Quadrajet Speak to Dean Oliver (870) 830-5470. Excellent and knowledgable Q-Jet builder and an easy person to talk to. __________________ Nelson Kowal Stock 345

12-16-2009, 12:08 PM	#3
Danny Ashley Member Join Date: Nov 2001 Location: Marion,In. Posts: 267 Likes: 60 Liked 110 Times in 29 Posts	Re: Thermoquad vs Quadrajet Larry, Thanks for the plug. Your new car looks great! John, I'v never heard of anyone comparing the Q-Jet with a Thermoquad so here's my opinion. Since both are rated at 800 cfm and if you had both properly jetted, it should be a wash. The engine doesn't know type just flow. You would have to compare a known good Q-Jet with a known good Thermoquad to know for sure. I assume that in the Thermoquad world as in the Q-Jet's, there is sometimes a big difference between cores. You could do up 5 of the same number and one would probably be faster. Dynos won't tell you either. The real test is the time slip. Period. If you choose to go with an Edelbrock, there are 4 numbers you can use; #1903, 1904, 1910, and 1905. The 1910 claimes to be an 850 but the primaries measure 1.218 which is what a 800 is. The 1905 is a direct replacement fot the Thermoquad on 1985 and earlier engines so it will have the correct linkage for Mopar engines. The Edelbrock are no longer manufactured and only occasionally will you find a new one from a parts supplier. E-Bay is a good source for used ones and sometimes there are new ones on there also. 800 cfm Quadrajets were used on a wide variety of GM engines from 301 to 455 in Buick, Olds, Pontiac, Cadilliac, and Chevy so if you know what to look for they can be found on E-Bay also. I stock new and used 800's. Don't be afraid to have someone outside California blueprint a Q-Jet for you as ther are a lot of good builders out there. Some of my Calif. customers include Grossi, DeFrank, Glassbrenner, Tim Smith, Bob Aceves, Bob Mulrey,and Ed Drucker . I'm not suppose to advertise on here so if you need my number maybe someone will post it or you can PM me. Danny

12-16-2009, 06:32 PM	#4
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 need a Q-Jet # 7040263 - 1970 Pontiac 49 state manual trans core. 1970 date, no superseded date code. Please email direct JeffLeeAzRealty@qwest.net __________________ Jeff Lee 7494 D/S '70 AMX

12-16-2009, 08:34 PM	#5
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; Go to customrebuiltcarbs.com. They're showing 7 in stock. Click on classic carbs, then Pontiac, then follow the charts. Danny

12-16-2009, 11:48 PM	#6
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 Thanks, I sent in a request for price quote. I know it's a bendover part, how bad do you think it will be? __________________ Jeff Lee 7494 D/S '70 AMX

12-16-2009, 06:01 AM	#1
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: Thermoquad vs Quadrajet Also consider talking with Danny Ashley. He post here and is an accomplished Q-jet builder. __________________ Larry Woodfin 471W

12-17-2009, 01:51 PM	#7
Jim Wahl Veteran Member Join Date: Jan 2002 Location: Central Florida Posts: 5,845 Likes: 672 Liked 683 Times in 129 Posts	Re: Thermoquad vs Quadrajet Remember, no matter which carb you choose, the primary and secondaries must be the same size as the original OEM carb. The 1 3/8 primary Thermoquad is actually rated at 750, where the 1 1/2 primary is rated at 800. Jim __________________ Jim Wahl....NHRA #2239 S/SS - IHRA # 8 Stock, D2 Stock Champion (forever I guess) 2019 Baby Gators Stock Champion 2009 NHRA D2 National Open Stock Champion 1982 NHRA D2 West Palm Beach LDRS SS Runner Up Past President, Southern Stock / Super Stock Association.