make a 30hp manifold into a 25hp

[fugazi kid]

i need a late 1950 split bug manifold,has anyone out there cut the ends off a 30hp manifold and welded on there 25hps ones. is this to good to be true,thay both look the same apart from the ends.

[splitjunkie]

even if you do the heat risers won't be correct.
_________________
Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[johnshenry]

Easier solution is to just "mill" the 36 hp ends to fit the 25hp heads. I have made a custom tool to do this. I am away from home right now but when I get home I can post a pic of it in this thread. You have to mill the endcasting OD down from 1.25" to 1.125" or around 29mm I believe. If you do this to a "701E" intake it will be fairly indistinguishable from the "701" 25 intake used in '52. See the intake matrix at zarwerks.com tech section. If you have an earlier car that is supposed to have K manifold it will look significantly different but it will work....
_________________
John Henry

'57 Deluxe
'56 Single Cab

[fugazi kid]

thanks john for your time on this,that tool sounds great,and a cheaper way on doing it,its better than paying $450 +pp for a repro! .ps how does this tool work.

[splitjunkie]

[johnshenry]

[johnshenry]

Here's some pics. Its a hole saw with the pilot bit replaced with a smooth high carbon steel shank on which is a wooden "cork" and spring.

The tool is chucked in a drill press and lowered into the bottom face of the endcasting. The cork centers in the casting hole, and the then the spring compresses allowing the saw to mill the outside of the casting. It works very well, but getting the intake clamped into a custom jig to hold it under the press at the correct position is a whole 'nother issue!!

The one in the pics had tooth section broken off, I have since replaced it.

_________________
John Henry

'57 Deluxe
'56 Single Cab

[Lazaa]

Hello,
I dig this thread to know if anybody ever tried to install a 25hp manifold onto a 30hp ?
All the topics I find are about the opposite swap.

I want my 30hp to be 25hp look alike. I have everything sorted (tins, shroud, fuel pump, D regulator, 383...Etc etc) but the K manifold.

It looks like the 25hp manifold sit quite OK on the 30hp heads so I wonder if the small difference of diameter between 25 and 30hp can be compensate by the aluminium seal ? anybody tried already ?

Thanks

[Zwitterkafer]

IIRC there was someone on here a couple of years ago who was lamenting poor performance with his 36hp engine....the cause turned out to be the replacement 25hp manifold installed on it. The reduced manifold cross-section and/or leaks at the head sealing rings were the culprit.
_________________
"Criticism comes easier than Craftsmanship"
- Zeuxius, 400 BC

[splitjunkie]

[Zwitterkafer]

I stand corrected.....there is indeed a tapered section in the 36hp manifolds that I checked. It's very nicely done too. So, leaks were more likely the culprit in the case that I posted about.
_________________
"Criticism comes easier than Craftsmanship"
- Zeuxius, 400 BC

[Mr. Okrasa]