Can 2.5 center drop manifolds be used on a SBC 2wd?

[chewychevy67]

My 327 engine build has changed direction a bit and now I'm looking to do something a little more peppy. That being said I need more breathing. Any of you guys successfully used 2.5" ramhorns on your 67 72 2wd trucks? Any starter issues? Post pictures if you have please?

[Grumpy old man]

I am ,There is plenty of room these are 2 1/2 " . You'll have to take it to a muffler shop for pipes I'm sure there is no kit that would bolt up , this is with the engine bolted into the front 350 position Not sure about if it was bolted into the L6 spot ?

[chewychevy67]

I am having a whole new exhaust put on at a shop so that's not an issue. I see that's a 67 frame too just like mine. That's good to know. Thanks for the pics

[chewychevy67]

Next question is will I be ok if I drop from 2.5 manifolds to 2.25 pipes? I was initially going to run stock 2" manifolds and go to 2.25"pipe but not sure if I want to choke it out the manifold. I really don't want 2.5"pipes all the way back. Guess I should add that my 327 will Be running aprox 330 hp at the flywheel.

[Mike C]

Why not go 2 1/2" all the way?

Your motor is approximately the same setup I have in my Jimmy. .030 327 with forged pistons using a large journal crank in a 4 bolt 350 block. 64cc heads so about 9.5:1 compression. Crane Energizer 266 cam (210 @ .050 .440 lift). Weiand 8004 intake with a JET stage II Q-jet and a small cap MSD ready to run distributor.

I replaced a set of Heddman headers, 2 1/4" exhaust system and some cheapie turbo mufflers with teh 2 1/2" 'vette manifolds, 2 1/2" system that exits 45 degrees to the frame past the rear tires and used the Hemi Turbo mufflers from Dynomax with the 20" case.

Not only is it quieter, It may have even picked up some low end power with no fall-off up high.

[chewychevy67]

Because I have my exhaust pretty much ready to put on. I just bought some 2.5" manifolds because the guy building my engine recommended it over 2" but it wasn't necessary just my call in case I decide to add to my engine in the future. I was thinking 2.25" to keep noise down. At least after the mufflers.

[chewychevy67]

Hey for you who have Done this did you use a mini starter or a stock size one? Also how hard is it to get to?

[shoveldug]

Originally Posted by chewychevy67

Hey for you who have Done this did you use a mini starter or a stock size one? Also how hard is it to get to?

Stock starter..............plenty of room

[chewychevy67]

Great. I didn't want to buy a new mini starter. Mine is all rebuilt and ready to go. If I had to go that way I would consider going back to the original angled horns.

[OregonNed]

This is an interesting read on manifold that straight drop in a '68, which should be the same as the '67. I was curious about clearance too, and also contacted the author to confirm. For what its worth.

https://www.hotrod.com/articles/1112...engine-exhaust