built up 251 finally in m37!!!

[justindearb]

I just wanted to talk about the project I just finished in case there are people out there thinking of doing the same thing, I just put a 251 in my m37 that I have been working over all winter. I got a 251 engine last fall, then I started to build it up a bit, I started by balancing and rebuilding it, then I pulled out the stock camshaft and sent it to Delta camshaft in Tacoma WA, it cost about $70 to regrind the cam to a 400m grind which was explained to me to be a marine spec cam that was the highest HP and TQ in a stock application that was put in the Chrysler flathead, this is a grind that gives you hp and tq without loosing any low end tq it is an awesome grind I love it!, this engine also has sodium filled exhaust valves and hardened seats, then I gasket matched ported the intake and exhaust and block to help airflow, I shaved the cylinder head .060 to raise the compression ratio and this engine is also a full flow block so I installed a remote wix spin on oil filter, the only modifications I had to make to install this engine was drilling new holes in the frame for the front engine mount to bolt in and I also got rid of the stock radiator fan and installed a electric pusher fan 12" 2300 cfm on the outside of the radiator (not what I wanted but it was worth the performance gain not spinning that old fan was worth it) the manifolds I have are what I call civilian manifolds having a 4 bolt flange exhaust manifold and I higher rise intake which I had to make a flange that bolts to the carb with a 2.5 exhaust pipe welded too it so I could mount a clamp on paper air filter now I have plenty of airflow and hood clearance and the engine also has a 10.5 HD clutch from ab linn I must say it is an excellent product the clutch is bigger in diameter and the pressure plate springs are much stiffer making a harder petal but gripping very very well love it! I speculate that iam getting 135-140HP and 240-250 TQ judging by stock 251 engine HP and TQ specs with the addition of the advertised gains from cam higher compression porting ect....

SO THE RESULTS!!!
if there is anyone out there who is on the fence about doing this engine swap my opinion is DO IT DO IT DO IT!!! THE PERFORMANCE GAIN IS SUBSTANTIAL! it is the single best thing that I have ever done to the truck there is a hill I my town that I used to hit the bottom going 45mph and by the time I was at the top I would be going 35, now with the 251 I hit the bottom of the hill at 45 and iam doing 47 at the top this is a huge improvement over the 230! and the cool thing is I still have room for improvement by the way of 2 carb setup and headers/custom 2 outlet ex manifold. I had many options for a different engine to put in this truck V8,4bt,slant six ect ect but I went with the big flathead I personally think it is the coolest engine for the truck nostalgic flathead with more modern power and stillget that awesome flathead six sound that I love, don't get me wrong 4bt's are bad ass but this is the path I went I just wanted to share my results with everyone!

please let me know what you think thank you.

 

[combat32]

It sure looks good, I have a fresh motor in my truck so will stick with my stock 230 for a while, in the meantime I will keep my eyes open for a 251 for the future. What all vehicles had the 251? I know the put them in the Canadian trucks.

 

[justindearb]

they where in a ton of things like massey combines, Desoto cars, forklifts, bombardier snow cats, Windsor cars, I lucked out by getting a block that was set up for full flow oil I guess only 10% of the flatheads had it so ive heard

 

[ranger.41]

Thanks for posting. Excellent job!

 

[JimC2]

I used to have one in a 1954 Chrysler Windsor. They were good engines.

 

[vtdeucedriver]

Cant wait!!

 

[pwrwagonfire]

I always said if I changed my engine I'd do a 251 instead...then I acquired a 230 for a deal I couldn't resist. Looks good! Keep the picture coming and enjoy!

 

[nhjohnny1]

PPPFFFFFFFTTTTTTTTT.........

Sorry im late, would have been here sooner but I didnt know you could read and write......

 

[snowman1494]

I am looking at doing the same thing with my m37, I just blew up the old 230 and have a rebuilt 251 I can use. I was told I cant use my original tranny; is this true? also could you tell if it is possible to use the original fan or will it hit the rad? I want my truck to look as original as possible. Thanks!

 

[justindearb]

The transmission bell housing are identical the only thing you may have to deal with his flywheel and clutch and pressure plate set up if your 251 already has a clutch and bell housing installed you'll be all set, my 251 originally wasn't industrial engine and it had a dual pattern flywheel so 10 1/2 10 or 11 inch clutch would fit so if your pressure plate doesn't fit on your new flywheel you may have to go to a different clutch that will fit your flywheel midwest military should be able to help you out with that, as far as the radiator fan goes Iran and electrical pusher because I didn't want to lose any horsepower since I was going for Max performance but you can either move the radiator to the outside of the sea channel that it's mounted to already you just have to drill new holes or resolder The Mounts on the radiator back a couple inches so you can clear the fan, I thought I heard that you can take the fan spacer out and it will fit but it seems like it'll be too close for my comfort

 

[snowman1494]

Ok awesome! Thanks for the reply. Now I just have to decide what to do... Either way Ill do some performance mods like you did.

 

[justindearb]

You won't regret it there leaps and bounds ahead of the 230

 

[Juskatla]

As already stated. the CDN M37s family all had 251's as an improvement over the US design, along with the T98 transmission and hardtop as standard equipment for our area of operations. Other vehicles that used the 251 were Dodge Power Wagons of various years and industrial equipment from fork lifts to marine applications. These were simple engines but powerful enough to use in many applications.