I am hoping that some of the Holley carb experts out there can answer a couple of questions to help me solve the problems on my '67 stock 327/350 with R-3810 Holley carb (dated 267). First, which are the correct base gaskets, which is the correct order of installation and where can you now purchase them ? In an attempt to solve a secondary bowl fuel percolation problem, I added a second base gasket. It seems to have worked, as I no longer see the inside of the intake manifold being wet with gas after sitting. However, I still get a small quantity of fuel accumulating in one of the intake manifold pockets on the passenger side, which would indicate a very slow secondary leak. I have been over this carb several times to try and stop this problem. New needles and seats, double checking the float level (dry as there are no bowl sight plugs). In addition to this leak, the car can be a real bear to start after sitting overnight or longer. It just can't get enough fuel until it has been excessively cranked. I can crank the engine for 30 seconds and not smell any fuel. The fuel pump pressure and flow are fine. One would think that the carb must become bone dry from leakage and the bowls require refilling. But I can open the the throttle and get a healthy shot of fuel from the accelerator pump. Once the car starts (usually quite roughly at first) and the idle smooths out, it runs like a top. I believe that the problem is in this carb and nowhere else. Is there some mysterious flaw to these carbs that I am unaware of ? My previous car, a '72 LT-1 with an R-6239 Holley always performed flawlessly and started easily, even after sitting for weeks. What am I continuing to overlook ? Any assistance would be greatly appreciated..thanks in advance guys..
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Re: Yet another Carb Question..
Hi Craig,
I do not claim to be an expert on Holley carbs, but here is a suggestion, try setting the float level in the "secondaries" lower. Todays fuel (unlike fuels of yesteryear) contains additives that expand when heated. Also, this maybe related to the starting problem although I doubt it.
Hope this helps -
Re: Yet another Carb Question..
I am not a Holley expert, but... I have been told (proceed cautiously here) by persons more qualified than me, that the base of some Holleys tends to warp, allowing leakage, seapage, causing bad running symptoms. You can always pull you carb and using a good datum source check and see if the base is indeed warped. Secondly, on the hard starting problem, have someone pump the gas pedal while you look down the carb throat. Do you see gas being discharged into the venturi? If you don't then you definetly have a leak somewhere. This would indicate that you have to crank the engine over so that the fuel pump will put fuel back in the bowls, so the carb can put it into the engine.Comment
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Re: Yet another Carb Question..
Craig, My '66 327/300 was experiencing similar problems. (Hard starting when hot, seepage into and onto the intake, etc). I rebuilt it and monkeed with the float levels, idle screws, accelerator pump, etc. It turns out that my seepage was coming from the throttle bore shaft. I also suspect that the base was slightly warped. I guess the age of the carb finally caught up with it. I know that the throttle bore can be bored and rebuilt w/ a new shaft, but I just bit the bullet and ordered a new replacement Holley (#3367 for me). I put it on last night, and it made a huge difference. It runs like a new car. I'll just box up the original and when I am ready to do the frame-off, I'll send it to one one of the rebuilders for restoration.
Alex
'66 A/C CoupeComment
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Re: Yet another Carb Question. .
My thanks to Alex, Gary and Bob for their assistance and ideas. I'll certainly use your advice. I'll let you know when I've solved the problem. Might be springtime by then. Thanks again
Craig
'67 A/C coupeComment
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Re: Yet another Carb Question..
Craig----
Your '67 350hp/327 originally used carb gasket GM#3849825. This gasket has been discontinued for years and is unavailable through GM sources. However, it is available in reproduction from most of the major sources. Dr. Rebuild, cantankerous personality aside, is usually a good source for gaskets. I've found his gaskets to be quite accurate. To avoid "personality" conflicts, I usually order by FAX.
I believe that you're on the right track with respect to the use of the insulating gasket to help control the problems you're having. GM added these in 1970 for this very reason. Your 72 LT-1 even used a special insulator over and above the thick base gasket. This was metal shield, GM #3999259, which has also been discontinued, but is available from Dr. Rebuild. The thick gasket and heat shield were one of the primary reasons that your LT-1 carb performed so well for you with respect to the problems mentioned.
There are two problems with installing the insulating gaskets/heat shields. First, of course, they're non-original for your 67 application. Second, you have to fabricate a longer choke rod to connect your divorced choke to the carb choke lever.In Appreciation of John HinckleyComment
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It took me 20 years to figure this out.
When I started work in Houston in 1971, my daily driver was a 300hp '67 convertible with a.c. and a 4-speed. In most ways it was a dependable sweetheart, but the original Holley carburetor perculated like a tea pot after commuting on hot summer days. I would have to crank the engine for minutes if I wanted to restart it after a 30 minute heat soak in the parking lot.
I assumed that it was a bad carburetor and tolerated it until '74. Then I sprang the big buck ($75?) for another 3310. Same thing. After two more years of hot starting problems, I still couldn't believe it was a factory design flaw. After all, my prior Corvette (a '65 350hp)had come with a Holley and it never gave me hot starting problems. I even bought a third 3310 for the '67 at the outrageous price of maybe $130 only to continue having the same problem.
I realized twenty years later that the choke systems changed between '65 and '67. The '65 brought heat to the side choke from the exhaust manifold in an external tube, while the '67 only had the heat passage in the manifold, and it was within a few thousandths of the carburetor baseplate. There was also a big difference between the heat transfer ability of the '65 aluminum manifold versus the iron intake on the '67.
There's no point to this story. Except maybe the '65 system works better than the '67.Comment
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30 years later and I still can't type
The carbs I bought for my '67 were 3810's, not 3310's.Comment
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