Sparkiewalt

I recently purchased my first Mustang for my 15 year Old son. I have a 1967 GTO that I have had since I was a teenager, so he has always wanted a American Muscle Car. Anyway, I am not much of a Ford man, at least with cars, never had anything but Ford trucks. Any way I just do not know a whole lot about the late 60s early 70s cars/motors. I purchased the car and it has headers and a high rise intake with a 4 barrel carb. the rear intake gasket had blown out so I got a new gasket set for a 4 barrel motor, then I realized something was up, I then did some research and found out that I have a 2V motor. My Question is.. Am I gaining much with the four barrel and high rise or should I put a 2 barrel back on it??? I noticed the huge difference in the head ports which makes me think I may be just dumping fuel into a hole with not enough air flow. Any hints or advice about anything to do with the car would be appreciated.

jimkaray

Assuming the 2v motor is stock or has mild street/strip build the high rise or single plane is hurting not helping. The best match for the 2v heads with a mild cam cam is a dual plane intake with a 600 or 650cfm carb - vacuum secondaries are fine. A 750cfm dual pumper carb on a high rise intake for example would be totally overkill and wrong for the combo I'm suspecting you have.

Sparkiewalt

Yes you are correct, I have a 750 double pumper on a high rise intake. I figured it might just be killing my MPG. Would it be better to spend the money on a new intake and smaller carb or get a larger Cam? I could also get a set of 4 barrel heads, But I would still need a new intake for it. If anyone has a set of 4 barrel heads and an intake for a good deal I may be interested. The car is going to be a daily driver for a while, it will see a lot of Highway 70-75 MPH like maybe 30-45 mins a day. I am not sure what rear gear I have but it seems to be a highway gear.

jimkaray

That carb along with the intake is also killing your low end torque along with the MPG. The 4V headed motor needs to be a high rever to take advantage of those big ports. You'll need new headers for the 4V heads too. For a daily driver the 2V heads with single plane intake, 600cfm carb and mild cam will be plenty of fun. So yes that is where I would suggest you spend your money. The stock rear would likely be a 2.73, the 3.50 gear is a good compromise of performance & highway but remember you don't have an overdrive gear so gas mileage will suffer some. Should still be better than with the combo you have in there now though, its a classic example of thinking bigger is better rather than properly matching the components of the motor.

Sparkiewalt

yea my guess on the rear gear is a 2.73, That will keep my RPMs low on the highway. I am not sure exactly what carb/intake I have I will post it later today. thanks for all of the input it is very helpful.

Sparkiewalt

I have a single plane intake.. it is a Weiand X-CELerator Intake Manifold 7516. I have a Summit carb ..not sure if its the 600 or 750, I cannot find any numbers on it. I am having trouble with the intake, it is blowing out the front and rear gaskets. It looks to be the right one for this engine. any thoughts on how to stop the blow out??

CPTCO

650 is the biggest carb i would put on. I'd probably just pull the manifold and start from scratch. Put the high rise on Craigslist and hit summit racing.

jimkaray

I like that intake but its best if your motor is built to make power higher up in the rpm range. Any idea if the heads have been worked at all and what cam and valve springs are in there? Maybe all you need is gears to gt it in the power band.
I don't know what's causing the gasket issue. Are sure they are being installed correctly, is the manifold is being torqued to spec for the aluminum manifold?
See if Summit can help you identify it. See if they list the bore sizes on their site.

Sparkiewalt

I know that the guy I got the car from just replaced the lifters, I am not sure what other work was done. I may have over torqued the intake, Anyone know what FT LBS I should torque to?

jimkaray

See this thread, it makes sense to me. Make sure you're using good gaskets and torquing down in the proper sequence and steps.