Third gen frame diffrences IFS wise

[cerial]

I have an 84 c30 and it came with 16.5's on the front and the truck has a MDOT GVW of 15,400k from the previous owner.
During this winter I am refreshing a Buick 455 and putting an oil pan, exhaust, and accessories, etc, that I plan on dropping in during the spring. It has been done before. I know about the mounts, clutch and so on.

I will be using the stock manifolds and welding up my own exhaust from there. I might build some headers if I have enough time.

I want to eliminate as much guesswork as possible as well as eliminating wasted space(more about the oil pan here) making the drop in a true bolt it up and go.

I want to take a junk frame and cut off the the A-arms and then behind the transmission cross member so I have the exact same thing as my c30 frame.

I will be bolting the 455 and 465 into the cut up frame bending my exhaust around and moving accessories up and down as well as making my oil pan wider and deeper.


What I want to know and can not seem to find is if the c10/c20/c30 frames are all the same IFS wise or if they changed anything in the c30 frame relating to the IFS.

I did find this search relating to the 2nd gen.

http://67-72chevytrucks.com/vboard/s...d.php?t=139828

I have no idea on the my 84. I am hoping that most of the beef is behind the cross member so I can get away using a c-10 frame or something more common then a c-30 frame.

If I need to use a c-30 frame I will.

I see no reason why a c/c or standard would matter in front of the cross member. If it does in any way that would be helpful.

I know the cross member moved around a bit but that really does not matter much as I am focusing around the engine and transmission in front of the output shaft.

Does anyone have an idea if they changed anything in frames relating to the area I want to cut up and use as a reference?

[andrewmp6]

I know the c10/c20 frames are the same but the c30 is thicker.And the c30 engine cross member is different then the c10/c20.

[SCOTI]

Front x-members are interchangeable between a C10 & C30. A 1/2 ton front xmember will swap in where the 1-ton xmember was. One difference is the upper a-arm studs are 1/2" for C10's & 9/16" for C20/30's (I have a 1/2 ton front xmember installed in my 89 CC dually).

The C30 rails are 2" taller where the rails drop down under the front of the cab & the steel is thicker vs a C10.

For motor mock-up, as long as you use the same engine towers you should be good.

[cerial]

Here is my c30's engine cross member after I pulled the last engine out this summer. I purchased it 2 months before. This is what 3 cans of gunk HD degrease and car wash degrease with soap did not remove when the engine was in. The previous owner was a fan of coating everything in grease overfilling with the electric gun and such. The cross member lip was level with grease and the thing had a good 3/32nd coating of grease on every part of the frame all the way back to mid transmission.



Here is it at another angle after I used 5 gallons of simple green, 6 hours, and enough cotton rags to fill a common trash bag halfway up.




I went to the junk yard today and looked through a few empty engine bays. They don't look much different until I get behind the engine cross member where the frame dropped.

I need a c30 frame no compromise.

Thank you for the help andrewmp6

[mrolds88]

That Buick will make good torque. Just remember you have to open up the bearing retainer hole in the Buick bellhousing for a SM465 to fit. They have a 5 1/8" retainer OD.