1967 Tri-Power carbs

[Jeremy H.]

Just had a 435 car judged in Charlotte, got counted off for no vent tubes in the carbs and a phillips head screw down in the center carb. I never hjave been counted off for these things before. Both Nolan Adams and the Vette Vues books don't show any vent tubes. From everything I can find, there never was any vent tubes in the tri-power carbs and the center screw was phillips, not slotted. Can you 435hp owners see what you have? The single carbs have vent tubes, but not the tri-power. Thanks for your input.

Jeremy Hedges
#31711

[John H.]

Re: 1967 Tri-Power carbs

I've never seen a 2300 with a vent tube.

[Wayne M.]

Re: 1967 Tri-Power carbs

Also, A.Colvin's '65-9 book has Chev engineering dwgs of all the C2-C3 center and end carbs; none show bowl vents, and you can make out the X-slot pattern of a Phillips head on the center shooter screw. However, even the dwgs for the end List 3659's show this screw, although there are no accelerator pumps on these.

[Ridge K.]

Re: 1967 Tri-Power carbs

Jeremy, you asked for info from 435hp owners, but I'm sure your aware that L68 400hp engines carried the exact same Holleys.
Here are a couple pics of the original carburetors from my March built (140XX), 46,000 mile L68 400hp '67 convertible. These have been restored by Holley's in-house custom restoration shop with strict orders to re-use every single part after their replating and refurbishing. My contract had one single part listed, which couldn't be restored and re-used (one base plate housing).
That screw inside the center carb horn is phillips head.
Carb dates are: 3660 center 721
3659 ends 724 (both)
My car was put up on blocks in a barn sometime in 1979, until I pulled it out in the spring of 2006.
Hope this helps, Ridge.

p.s. sitting on a NOS GM 4382 intake manifold

[Clem Z.]

Re: 1967 Tri-Power carbs

i have rebuilt a lot of holleys in my life time and have never seen a squirter screw that was not a phillips except for some special industrial engine carbs.

[James H.]

Re: 1967 Tri-Power carbs

My 68s center carb had the breather and when I sent them off for rebuild, they told me to get rid of it.. Wasen't thinking of loosing points though. Looks just like pics posted.
I wonder if that was standard practice for 67s and 68s.

[Jeremy H.]

Re: 1967 Tri-Power carbs

Thanks for the replies, I just don't understand some of these judges.

Jeremy Hedges

[Wayne M.]

Re: 1967 Tri-Power carbs

Thanks for the replies, I just don't understand some of these judges.

Jeremy Hedges

Maybe you're right, Jeremy -- look what I just found in a Jan '67 issue of Chevrolet Service News . My reading of this is that '67 tri-powers installed on Corvettes prior to Nov 1st 1966; ie VIN 07186, SHOULD have bowl vent tubes on the outboard carbs.

What does the '67 TIM&JG say on this ?

[Clem Z.]

Re: 1967 Tri-Power carbs

the press in vent tube bring the bowl vents too close to the air cleamer top causing the carbs to richen up because the air can not get out of the bowl vents fast enought. that is why corvette 4 barrel holleys have the vent tubes cut at a 45 degree angle to allow more area in the vent tube for venting. when road or drag racing the 3 X 2 carb set up we had to add internal baffles to the front and rear carb to prevent fuel from coming out the bowl vent on hard acceleration. the center carb had a factory vent baffle installed but the end carbs did not

[Jeremy H.]

Re: 1967 Tri-Power carbs

Very intersting. I have another 400hp car that is to be judged and it is in the 6,000 range. Should I put the vent tubes in the carbs? I'm sure then it would get counted off.

Jeremy Hedges
#31711

[Wayne M.]

Re: 1967 Tri-Power carbs

Very intersting. I have another 400hp car that is to be judged and it is in the 6,000 range. Should I put the vent tubes in the carbs? I'm sure then it would get counted off.

Jeremy Hedges
#31711

A real predicament ! I'd play it safe (no vent stacks). Depends on what the '67 TIM&JG says (probably not mentioned at all). None of the shots in Noland's Vol 2 show vent stacks, incl. a GM pic on pg. 419.

Just to complicate matters, in Chev Service News of December 1967, there's instructions on how to adjust closing rods on 3 x 2 carbs. The photo shows VENT STACKS on the front/back carbs.

IMO, the early '67 tripowers had them -- otherwise why would there be complaints and a solution issued by Chevrolet ?

[Clem Z.]

Re: 1967 Tri-Power carbs

i worked on a lot of tri power corvettes back then but i never saw any bowl vent extension.

[Mark K.]

Re: 1967 Tri-Power carbs

Maybe you're right, Jeremy -- look what I just found in a Jan '67 issue of Chevrolet Service News . My reading of this is that '67 tri-powers installed on Corvettes prior to Nov 1st 1966; ie VIN 07186, SHOULD have bowl vent tubes on the outboard carbs.

What does the '67 TIM&JG say on this ?

If you mean Corvettes produced prior to Nov 1 that would mean up to VIN 2685, not 7186. My 435 (Vin 5304) was produced on December 6, 1966.

[Wayne M.]

Re: 1967 Tri-Power carbs

If you mean Corvettes produced prior to Nov 1 that would mean up to VIN 2685, not 7186. ...

You're right, Mark. I was reading the 1966 model year end of month production, in the NCRS pocket guide, rather than 1967 .

So by the silence of everyone, I have to assume that the vents [there / not there] are not mentioned in the '67 TIM&JG.

[Wayne M.]

Re: 1967 Tri-Power carbs

Remember this Campbell-Ewald (sp ?) '67 ad ?

Look at the vent tubes .