Carb Selection

[bmcgc1960]

After much discussion with my misses, we are going to do a rebuild on the 200 in our 65 couple with a c4 and 2.80 rear gear. We have only owned it for about a month. Its burning a lot of oil.

This is her car and she wants it to be period correct in appearence, reliable, and the best mileage she can get. I want to sneak some better performance in.

Currently we have a 65 block, 70 head, Holly 1940, I dont know which dizzy we have or what the cr is.

The car burns oil, has no power, and I cant get the carb adjusted. It ides to high, when I try and drop the idle, the car runs very rough. It will not drop out of fast idle unless I pop the hood and move the linkage by hand.

My plan is to keep the block, head, and oem log with the single exhaust. I just put a new 1.75 exhaust kit from CJ Pony on.

I would like to bump the compression and upgrade to a DUII.

What carb? I dont like the 1940 because I cant figure out why it stays in fast idle. BTW the PO installed the carb and it is new.

A 2v would be nice but I dont want to screw with the linkage and I dont know if I can find a shop here that can mill the head properly for the adapter. So what is my best bet for a 1v?

Keeping the single exhaust, should I bother with a cam? I dont like oem reground cams, I have never had good performance with them, but the misses doesnt want a header so Im not sure if a mild cam is worth it or not.

Basically, Im looking for the best performance I can get without killing the mileage and keeping it oem looking and sounding.

 

[65fback]

My car has a 1940. What dizzy do you have? My car has a newer carb and older dizzy so vacuum isn't right.

As for fast idle I have same problem but I've found if I goose the gas it drops down into regular idle just fine and stays there. If that works it would give you time to look for a better carb.

 

[CZLN6]

Howdy Back:

Are you planning to keep the C4 and the 2.80:1 rear gear? IF so, I'd suggest that you freshen the C4 and add a shift kit to tighten it up. On the carb, you have the choice of the stock 1970 Carter YF rated @187 cfm. Or you can increase CFM with a YF or RBS from a Maverick with a 250. Both are rated @ 215 cfm.

For your goals, getting the compression up will be a big key part to success. I don't know your elevation, but go for at least 9:1 with a stock cam, or slightly higher depending on your other details.

The '70 head will have 1.64" intake valves, which are fine for your goals. But, their performance can be helped by a back cut, on rebuild.

I'd suggest a DuraSpark II ignition system, recurved as per the "sticky" on this forum.

IF you decide to upgrade the cam stick to a cam with about 256 duration, .400" to .425" lift, and a 108 - 110 lobe angle separation. An aftermarket performance cam will have steeper ramps on the lopes, opening quicker and staying at higher lift longer. IIWM, I'd also add an adjustable rocker arm assembly to get the most out of the valve train. This set up will offer a noticeable performance boost in the lower rpm range. With a stock exhaust manifold this all fits.

Dropping the rear gear to a 3:1 would be a nice, around town improvement. Good luck and best wishes. Keep us posted on your progress.

Adios, David