dhartley72

Hello i was wondering what went wrong......i brought a set of JR headers and the driver side will not bolt on....its hitting the frame..the passenger side fits perfect.....is there anything i can do to get them to fit.... has anyone had this type of problem before?

rocketraider

Did the original engine have a motor mount spacer between mount and block on either side? and if it did, is it there now?

It's generally accepted that most headers will require some massaging to make them fit right, which almost negates the benefit of having them.

Rickman48

If it's hitting the whole rail - it's better to make them oval than to put a 'dimple' in them, and heating them w/a torch makes that easier, too.
Of the 20+ sets I've installed, probably had to modify 6 - 7, in some way!

dhartley72

the motor mount is still there....but i dont see a spacer....where can i purchase the spacers from.....and yes its hitting the frame rail....i think maybe if it had 2 inches it would clear

Oldsguy

Are those big block headers or small block headers?

joe_padavano

Let's back up. What year/model of car?

Also, virtually NO Oldsmobiles use spacers between the motor mount and the block. Is the 403 original to the car, or was it swapped? Are the motor mounts and frame mounts correct for the application? Are the headers correct for the application (a 403 is a small block Olds and should use 350 headers)?

dhartley72

okay the orignal engine was a 350.....when i purchased it...it had a 403 in it..so yes it was swapped...i ordered headers from doug herbert and they sent me jr headers...i told them my engine is a 403...and the told me the 350/403 is interchangeable....my car is a 72 cutlass supreme...what more can i do...the passenger side fit perfect

rocketraider

Joe. Guess again. My Custom Cruiser (350 diesel converted to 350 gas) has one on the left side, as do my 76 Ninety Eight and my 74 350 Hurst, both of which have their original engines. The 1973 455 Delta convertible had one on the right side. These cars came from three different assembly plants.

Believe me when I say they made a motor mount replacement job more complex. The spacers like to fall out until you can get two bolts started.

I have often wondered if this is where that Supreme offset engine nonsense came from. I don't think a buddy's 72 350 Supreme had any, but it was twenty years ago when we pulled that engine and the car's been gone for ten.

joe_padavano

Which is why I said "virtually".

The diesel cars have the spacer bracket on the driver's side to move the motor mount forward to clear the larger diesel starter. If you get tired of dealing with it, you can always move the frame mount back to the gas engine position and remove the spacer bracket. Note that neither of my 307 B-body wagons have spacers.

The spacers for the 71-76 full size and 73-77 A-body cars are shown in the parts book. I assumed that the Supreme in the OP's avatar was the car in question, and I can guarantee that no 64-72 A-bodies used spacers.

dhartley72

Will I have to move my starter etc...any modications????

joe_padavano

The header is hitting the frame where, exactly? It is normal to have to relocate the brake distribution block located on the inside of the driver's side frame rail.

dhartley72

it hitting the inside frame rail therefore i cant push it forward towards the front of the car..

joe_padavano

I'm afraid you'll need to be more specific than that to get a useful answer. Is it hitting on the mount for the lower control arm? The brake block? The crossmember? The mount for the trans linkage?

Usually you will need to raise the engine on that side to slip the header into place, then loosely bolt it up and lower the motor back down before tightening it. It also helps to get the steering shaft out of the way while you do this.

dhartley72

okay...i figured it out ...im going back with my stock exhaust manifold and run true dual from it.........