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intake manifold for 251 c. i.
Posted: Fri Aug 30, 2013 7:50 am
by m37jarhead
Howdy:
The 251 c.i. engine in my M37 is up and running. Pulls strong.
The engine came from an early '50's Chrysler Windsor.
Horse power supposed to be 130... give or take.
Problem is, the intake manifold stands proud and with
the stock military air cleaner installed, it prevents the
hood on the M37 from closing.
So, my question is: Would an intake manifold from a military/Canadian 251 c.i.
engine have a shorter profile and allow the air cleaner to clear the underside
of the hood?
Anyone with a 251 that could give me some measurements?
Jerry
Re: intake manifold for 251 c. i.
Posted: Fri Aug 30, 2013 8:26 am
by achiem37
My CDN M37 251 engine has the carb mounting surface at the same height as the head/block joint. The carb gasket surface is about 1/8" above the cast intake runner heights. I can send you some pics if you want. This engine is out of the truck and sitting on a stand. Terry...email at
t__acheson@sympatico.ca
Re: intake manifold for 251 c. i.
Posted: Fri Aug 30, 2013 9:20 am
by RMS
the military intake has the lowest profile of the three 251 single "down draft" carb intake manifolds that I"m aware of.
this is a stock m37 manifold, low

medium

high

Re: intake manifold for 251 c. i.
Posted: Fri Aug 30, 2013 12:23 pm
by m37jarhead
Thanks for the info Terry and RMS.
Went out and looked at the intake manifold on the 251 Chrysler Windsor.
Sure enough, the top of the manifold where the carb attaches is almost
level with the TOP of the head. 2" higher than the joint between the head
and the block. Thanks for the pic's.
I guess I'll be looking for a military 251 intake manifold.
I'll try to post some pic's of my set up. It works just fine
but the rinky-dink air cleaner looks out of place.
Jerry
Re: intake manifold for 251 c. i.
Posted: Fri Aug 30, 2013 1:34 pm
by RMS
m37jarhead wrote:
but the rinky-dink air cleaner looks out of place.
Jerry
careful going up and down steep grades, if its the small shallow oil bath that you are running. as it will leek before the carb starts to sputter.
I would be inclined split the manifold and inspect the exhaust before resigning to only needing an intake. I have seen many broken during separation

Re: intake manifold for 251 c. i.
Posted: Sat Aug 31, 2013 11:08 am
by m37jarhead
Here's a pic of the 251 Chrysler Windsor intake manifold installed on my M37.
Note the straight edge on top of the head is the same height as the top of the intake
manifold. You can see this maniflold is at least 2" higher than on the pic's posted by RMS.
Problem solved but now I need a military 251 c.i. manifold with the lower profile.
Anyone have one for sale???
Jerry


Re: intake manifold for 251 c. i.
Posted: Sat Aug 31, 2013 11:11 am
by m37jarhead
RMS wrote:m37jarhead wrote:
but the rinky-dink air cleaner looks out of place.
Jerry
careful going up and down steep grades, if its the small shallow oil bath that you are running. as it will leek before the carb starts to sputter.
I would be inclined split the manifold and inspect the exhaust before resigning to only needing an intake. I have seen many broken during separation

No, the rinky-dink air cleaner is a dry, paper filter. For now it keeps the birds out of the intake.
Thanks,
Jerry
Re: intake manifold for 251 c. i.
Posted: Sat Aug 31, 2013 2:56 pm
by RMS
m37jarhead wrote:
looks like you've had the manifold apart
Id like to help you out with a manifold but all I have left is two medium rise intakes. it might fit being that it is only 3/4 of an inch taller than stock. however shipping 10lbs from canada on a maybe is a pricy proposition
RMS wrote:
I noticed you studded the head. what kind of fasteners did you use?
Re: intake manifold for 251 c. i.
Posted: Sat Aug 31, 2013 4:00 pm
by m37jarhead
RMS:
The studs came from Vintage Power Wagon. No cap screws in the kit.
I used cad plated nuts and flat washers with Lock Tite. I DID re-torque the nuts after
running it up to temp. The engine came with all studs and nuts. (?) Don't know
if this is correct but the engine ain't Mil. Spec. anyhow.
So far.... so good.
Yes, 10 lbs., might cost more than a 12 pack to ship but it may be worth the try.
When I tried to use the oil bath air cleaner it was only and inch or so from
clearing the inside of the hood. Your pic. makes me think it MIGHT work.
Jerry
Re: intake manifold for 251 c. i.
Posted: Sun Sep 01, 2013 10:06 am
by m37jarhead
Here's a pic of the "high rise" manifold and the rinky-dink air cleaner.
Jerry

Re: intake manifold for 251 c. i.
Posted: Mon Sep 09, 2013 6:29 pm
by RMS
did you steal that filter off your compressor ? If you cant find a intake locally I can ship one to you for the cost of shipping and gas.
Re: intake manifold for 251 c. i.
Posted: Wed Sep 11, 2013 4:10 am
by skinnedknuckles
Jerry I think that I have an intake that will work, I'll look tonight. It was on one of my m37's that I bought for parts and it had a 251 cobbled into it.
Paul
Re: intake manifold for 251 c. i.
Posted: Wed Sep 11, 2013 12:47 pm
by Master Yota
As a final option, is there enough material available to have the mounting surface machined down to the lower height? Is the taller intake common enough to try this as an experiment?