65 Big Block Headers

[mtnxtreme]

Can anyone tell me what headers will fit a big block in a 65 2wd chassis with 61 cab, something that will not hang too low as the truck is lowered, and do I need special motor mounts for clearance ? The truck had a small block before so I don't think those mounts work anyway !? I have heard Chevelle headers work ?!

[SCOTI]

Look for 68-72 or even 73-80 a-body Chevelle/Malibu headers. They tend to work well for GM truck apps as well like your 65 chassis. The full length variety might be just below the frame rail still but they're usually tucked higher/tighter vs the truck headers.

Both truck & car headers are also available in a 3/4 length (also called mid-length or shorty headers) to help on clearance issues under the floor. They might create other routing obstacles since the collector is higher up but if clearance is needed, they do help. The 3/4 or mid-length are usually not available in the larger primary tube sizes though if that's a consideration.

Food for thought.

[mtnxtreme]

Should I keep my small block mounts, which I was told will work but sit a little higher, maybe would help with clearance ? Or get the big block mounts that set the motor lower ?

[SCOTI]

Originally Posted by mtnxtreme

Should I keep my small block mounts, which I was told will work but sit a little higher, maybe would help with clearance ? Or get the big block mounts that set the motor lower ?

It really would be your call based on what's more critical (or available) as far as space.

Sometimes the induction system and/or trans bellhousing need more room to clear so getting the drivetrain lower would be helpful. But, the lower the block is in the chassis, the lower the exhaust would be where it exits.

Me personally? I would validate both if I think one position might be more beneficial. If you already have small-block mounts, I'd roll w/them & see what you think. Go from there.

[Captainfab]

If you mount a big block in the stock small block location, you will have to modify the firewall. If you don't want to do that and move the engine forward, you can use '68-'71 big block brackets and mounts or the '73-'87 brackets and mounts from a C20 or C30. Those fit the early frames better than the C10 brackets. As for the headers, I used Hedmans for a '73-'87 but they are long tubes. You can use the Chevelle headers as long as you are going with an auto trans.

[mtnxtreme]

Originally Posted by Captainfab

If you mount a big block in the stock small block location, you will have to modify the firewall. If you don't want to do that and move the engine forward, you can use '68-'71 big block brackets and mounts or the '73-'87 brackets and mounts from a C20 or C30. Those fit the early frames better than the C10 brackets. As for the headers, I used Hedmans for a '73-'87 but they are long tubes. You can use the Chevelle headers as long as you are going with an auto trans.

Ya I definitely don't wanna mess with the firewall. I'm using a manual trans so I guess the Chevelle header idea is out. And I'd rather long tubes, how tight did they fit, did they hang down much ?