Fed up with tri power

[Michael V.]

Re: Fed up with tri power

My girlfriend bought a 1967 427/400 with a powerglide in 1974 with 38,000 miles on it and drove it for 5 years everyday to work with no problems.

[Gene M.]

Re: Fed up with tri power

All------


As I've said before, you'll notice that GM did not use 3X2 on the really high performance big blocks, the L-88 and ZL-1. For those, it was a single 4 barrel. There's a message in that.

Right you are Joe. On display with three duces is just a peacock with his feathers all spread out. All looks and nothing added for performance.

[Rich G.]

[Mark E.]

Re: Fed up with tri power

Thanks guys; this is one of my favorite threads.

I especially liked the 2 barrel L71 suggestion.

[Doug H.]

Re: Fed up with tri power

I was ready to give up on my 1967 tri-power fuel lines also, until I tried the 3/8th in. FLAT copper washers that one member recommended. It worked perfectly! After twenty years, I have no leaks and no gasoline smell in the garage. No need to locate the HTF flared washers. For less than one dollar, you can buy three flat ones, and they are available everywhere.

[Rich G.]

Re: Fed up with tri power

I had started another thread where I reported all is well. Should have linked it here I guess. I ended up having both end carbs rebuilt. I installed them, connected fuel lines and linkage (tip: hook up the linkage BEFORE installing fuel lines.) �� and adjusted idle mix and idle. The car has been running great all summer. Idles around 700. No run on. No leaks. No gas smell in the garage.
I have attended many cruise in shows all summer and Ive met a few guys running with the end carbs blocked off.

The guy who rebuilt the end carbs said the floats were set too high and that he sees that a lot when he gets them in. I’m sure that’s not the only thing that was wrong.

https://www.forums.ncrs.org/showthre...e-my-car-again

Rich

[William M.]

Re: Fed up with tri power

"THREE HEADACHES"!!!!!!!!! That is what the 3x2 set-up was called in the late 1960's-1970's! Back then Corvette owners would come to me to pay me to replace their 3x2 set-up with a single Holley 4-barrel carb and intake and give me the 3x2 set-up. I used to have 3x2 set-up stacked like cord wood. The same went for FI Corvettes(replace the FI unit with a 4-carrel carb). I also had FI units stacked like cord wood. Also, the same with knock-off wheels coming loose. Corvette owners would have me replace their knock-offs with stock rims and hubcaps and give me the knock-off wheels including the spare and KO hammer. I had knock-off wheels stacked like cord wood. Usually the problem with knock-off wheels coming loose is that short lug nuts were used to attached the adapter rather the the long lug nut part #3852554.
Bill Mock #93

[Jaime G.]

Re: Fed up with tri power

"THREE HEADACHES"!!!!!!!!! That is what the 3x2 set-up was called in the late 1960's-1970's! Back then Corvette owners would come to me to pay me to replace their 3x2 set-up with a single Holley 4-barrel carb and intake and give me the 3x2 set-up. I used to have 3x2 set-up stacked like cord wood. The same went for FI Corvettes(replace the FI unit with a 4-carrel carb). I also had FI units stacked like cord wood. Also, the same with knock-off wheels coming loose. Corvette owners would have me replace their knock-offs with stock rims and hubcaps and give me the knock-off wheels including the spare and KO hammer. I had knock-off wheels stacked like cord wood. Usually the problem with knock-off wheels coming loose is that short lug nuts were used to attached the adapter rather the the long lug nut part #3852554.
Bill Mock #93

Well I must have missed on this precious cords of wood available. I have a tri power L71 with no issues, have had 5 FI cars with no issues, have 2 KO wheel cars with no issues. If you have the right people work on your cars and stay away from ethanol fuel these options function quite well.
Too bad for those of you that dont enjoy the feeling of the tri power setup kicking in or the FI gliding down the road. If you dont like these setups why have the cars. Buy a base motor automatic.

[Joe L.]

Re: Fed up with tri power

As I've said many times before, if the 3X2 was such a great system performance-wise, I wonder why GM used a single 4 barrel on the L-88 and ZL-1?

[Dereck S.]

[Joe L.]

Re: Fed up with tri power

I’ve had my 67 427/400 for 33 years. Every issue you’ve indicated I have experienced and continue to experience. Fuel leaks are common especially after the car sits for extended periods and the fuel in the bowls evaporate out. Gaskets dry out and shrink then leak. Significant fire hazard if left unchecked. Fuel line fittings at the bowl also leak. Secondary butterflies stick slightly open causing higher idle. Float needle valves allow fuel to drip into the venturies and cause flooding. I’ve seen all the issues. My 70 Challenger with a four barrel have none of those issues. However, the tri-power setup is the coolest , sexiest carb arrangement ever devised. I’m aware of all the issues and know how to identify and manage them. I put 1200 miles a year on the car which helps. Sitting for 6 months over the WI winter is a major problem. I rebuild my original 681/691 dated carbs every 3 years. I’m always watching for fuel leaks. Drive it as much as you can and do the best you can to manage the issues. If they become too much to deal with put on a four barrel. I could never make that switch. On a side note I have no power steering. I’m absolutely sick of the manual steering and plan on adding power steering over the winter. I can certainly understand wanting to address anything that distracts from enjoying the car. The tri-power can certainly distract from that enjoyment.

Dereck-----


A stock-type power steering will be the best change you ever made to the car. I guarantee it. I did it once myself to my original owner 1969 and it was the best thing I ever did. The second best thing I ever did was to add a soft-top to the car that I originally ordered as a hard-top only.

[Rich G.]

[Dereck S.]

Re: Fed up with tri power

Something I considered trying to address the effects of having the fuel evaporate out followed by a drying and shrinking of gaskets was to fill a squirt bottle with gas and manually periodically fill each carb via the vent tube ports at the top. Based on experimentation I determined that it only takes about 2 weeks for all the gas to evaporate out of each bowl. Initial evaporation occurs at a faster rate immediately after the engine is shut off and the aluminum intake manifold and carbs retain heat. I should point out that I've always retained the original heat riser in the exhaust manifold. That keeps the intake and carbs very hot. Non-operation evaporation rate varies based on environmental conditions. The intent of filling the carbs manually would be to keep all fuel exposed gaskets and rubber seals wet with fuel and swollen. Perhaps something to try next winter.