What is the correct angle for the engine/carb?

[Extended Power]

If you have read my post on how my new engine wouldn’t fit, you heard how it hit the firewall, as well as the heater housing.
I moved the engine mounts forward by one inch, and have removed the heater housing. (Installing Vintage Air)
Even after moving the engine forward by one inch, the right valve cover is STILL very close to hitting the delete plate.

My truck had the factory big block, with t-400.

I have moved engine mounts forward 1”.

I also have a custom transmission crossmember that has the correct 3* angle to mount the transmission.

My truck has 3” lowered A-Arms in front, and 4” drop in the rear.

Should/could I raise the transmission rear mount a bit more to gain more clearance behind the right valve cover?

I would think that with the truck sitting on level ground, the carb flange on the intake manifold should be level...

Opinions, answers, or other?

[bowtie72]

It is really gonna to depend on driveline angle. If you raise the trans it’s going to affect the driveline angle and could cause a vibration.if you have no vibrations and it isn’t touching I would leave it.

[Steeveedee]

Yes, the carb should be level when you are on level ground. That may have a ripple effect on other things, like the driveshaft angle, as mentioned.

[HO455]

With all the work you have done checking the driveline angles is a must do item. You can't go by how level the carburetor looks to be. Small 2 degree changes can make a big difference in the truck's NVH. A nice smooth truck is just more enjoyable.

Here is a link to how I checked mine and what I needed to do to reduce the vibration. (There were other issues that needed attention too ). Scroll to post 348 to start.

http://67-72chevytrucks.com/vboard/s...698377&page=14

Hopefully you will be able to gain that valve cover clearance you need.

This Spicer calculator and videos as well as others helped me to get mine where it needed to be.

https://spicerparts.com/calculators/...gle-calculator

https://4xshaft.com/blogs/general-te...veshaft-angles

[Extended Power]

Truck was lowered 3 in front, 4 in back, with no changes...thats why I believe I could raise the transmission a bit.
Also...haven't started or ran truck on street with the additional drop in the rear yet, so can't tell if driveline is out of wack yet.
And another curve...if it is, I'd probably change to a single piece driveshaft.
If I get the clearance I need first, then fix the angle, if required, sounds like the most effective way to go.

[HO455]

Having gone through the driveline angles dance several times over the years personally I would jump under the truck and do a quick check of the current engine/transmission angle and also the pinion angle. Compare the two angles. You want them to be within 1.5 degrees of each other. And the closer the better.

If they are in spec then anything you do to the engine to gain clearance will mean that you will have to adjust the pinon angle to match.

There is no guarantee that your current set up is anywhere near correct. 50 years of BBC torque and general wear and tear hasn't left your frame unmolested. Add in tolerance stacking for all the mounting points and perfectly manufactured aftermarket parts it's hard to believe that it could all bolt together and be aligned. Lowering the rear moves the pinion angle down from the factory 2 to 3 degrees up to zero or a down angle depending on how low you go.

In my world it never works out that way. Most folks have more coupons than me.

I converted to a one piece drive line after I installed a Gearvendor unit. There may some information in the link starting at post 671 that may help you.

http://67-72chevytrucks.com/vboard/s...698377&page=27

[Extended Power]

I’d love to check the angles....but I no longer fit under the truck when it’s sitting on the tires.

I guess I’m gonna have to make some equal height blocks or something. (I do have the 5K vehicle dollys, but it’s still a tight squeeze.)

Thank you for the information though, that will definitely be useful!

[Ironangel]

I took a set of small block stands and welded a 2-1/2" piece of horizontal tube. The standard 3 bolt plates w/7/16" holes in 2 gussets...A motor tilted back a couple of degrees helps keep that oil flowing to the back of the motor. If you have a two piece drive shaft, the first shaft should line up with the crank centerline out to the carrier bearing. Last two u-joints cancel each other out.