Sponsored Content
V
Former Member
Send PMMounds View, MN - USA
Joined: 5/24/2007
Posts: 1034
Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
I also agree with Joel. It sounds like a flooding problem that can be fixed.
If you do decide to replace the carb, the hot new carburetor is the Barry Grant. The local GM Performance Parts dealer carries them. We have sold several of them, and the owners were all very happy. Barry grant is a Holley expert who designed his own carb fixing all the little things he didn't like about Holleys. They are usually priced competitively.
Larry
If you do decide to replace the carb, the hot new carburetor is the Barry Grant. The local GM Performance Parts dealer carries them. We have sold several of them, and the owners were all very happy. Barry grant is a Holley expert who designed his own carb fixing all the little things he didn't like about Holleys. They are usually priced competitively.
Larry
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
SPONSOR AD:: (Our Sponsors help support Vette Registry)
J
Free Member
Send PMMAPLE, Canada
Joined: 3/9/2008
Posts: 164
Vette(s): 70 VETTE 350/300HP, AUTOMATIC, ALL STOCK EXCEPT FOR MILD CAM,LAGUNA GREY, 3:55 POSI GEARS
I WAS THINKING MAYBE IT IS A VENTING PROBLEM WITH MY TANK. I DID INSTALL A NEW TANK BEFORE IT WAS PUT AWAY, I DONT THINK ANY OF THE HOSES WERE PINCHED. WHEN I TAKE IT BACK OUT I WILL LEAVE THE GAS CAP OPENED A BIT, IF THERE IS A VENT PROBLEM I WOULD NOTICE THE DIFFERENCE. WHAT ELSE CAN I LOOK AT WITH THE VENTING SYSTEM?
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
Lifetime Member
Moderator
Send PMModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 22742
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Should your car have a vented cap? Not sure about all of the '70 cars, but I believe some of them had non-vented caps(LT1s?), and some had vented caps.
Certainly, too much vapor pressure in the tank could cause your problem...my '85 has a similar issue with the tank vent (that I haven't taken the time to clean yet
), and I have to loosen the gas cap every time I park it for a while, and I leave it a little loose while driving. It builds up quite a bit of pressure in there! Adams' Apple 2008-03-11 20:05:10
Certainly, too much vapor pressure in the tank could cause your problem...my '85 has a similar issue with the tank vent (that I haven't taken the time to clean yet
), and I have to loosen the gas cap every time I park it for a while, and I leave it a little loose while driving. It builds up quite a bit of pressure in there! Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
J
Free Member
Send PMMAPLE, Canada
Joined: 3/9/2008
Posts: 164
Vette(s): 70 VETTE 350/300HP, AUTOMATIC, ALL STOCK EXCEPT FOR MILD CAM,LAGUNA GREY, 3:55 POSI GEARS
I HAVE A NON-VENTED CAP, I THINK UP TO 69 HAD THE VENTED CAP. WHAT IF I PUT IN A VENTED CAP?
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
Lifetime Member
Send PMSummerville, SC - USA
Joined: 8/31/2005
Posts: 660
Vette(s): My 1974 Vette sold last August 2014. I am still willing to show up to events and local gatherings if anything happening No new vette yet.
My '74 came with a Holey on it. they run rich but are great carbs. What happened to your original rochester? or getting another one? When i bought my car the previous owner gave me a box with parts in it and the carb was in there dirty and oily. i sent it out and got it rebuilt to factory settings and it is whats on my car ever since. no problems at all. Holley is sitting in a box. It is obviously up to you.
As for the gas cap, my '74 doesnt have a vented cap and has no problems. yours probably didnt come with one either seeing as how it is a '70.
Jeremy H.
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
Venting of the cap was not based on the year, it has to do with fuel vapor recovery, and fuel returned to the tank. My LT1, as Joel mentioned, has a non-vented cap, but my L-46 has a vented cap because of the fuel return line from the pump. All Q-Jets had return lines, Holleys did not.
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
Lifetime Member
Moderator
Send PMModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 22742
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Thanx for the clarification, Mike! 
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
J
Free Member
Send PMMAPLE, Canada
Joined: 3/9/2008
Posts: 164
Vette(s): 70 VETTE 350/300HP, AUTOMATIC, ALL STOCK EXCEPT FOR MILD CAM,LAGUNA GREY, 3:55 POSI GEARS
HOW HARD IS IT TO ADJUST THE FLOATS ON THE EDELBROCK CARB,SOMETHING I CAN DO ?
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
[QUOTE=JC VETTE 70]HOW HARD IS IT TO ADJUST THE FLOATS ON THE EDELBROCK CARB,SOMETHING I CAN DO ?[/QUOTE]
If you go to the Edelbrock web site, you can download a complete manual in PDF format. The float (or floats) are not hard to adjust, but you will have to remove the top of the carb. There is a complete troubleshooting guide in the manual.
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
Lifetime Member
Send PMSummerville, SC - USA
Joined: 8/31/2005
Posts: 660
Vette(s): My 1974 Vette sold last August 2014. I am still willing to show up to events and local gatherings if anything happening No new vette yet.
What happened to the rochester for the car?
Be the first to like this post
Sign In to Like this post
Sign In to Like this post
in Forum: C3 Engines, Driveline and Handling
Sponsored Content