Engine swap

[notjustair]

Grain truck is a 1958 GMC 370. It has the straight 6 in it. It has had a cracked head for quite some time and I am getting sick of thinking about it. Anyone know what carb engine is a bolt-in for that 4 speed trans?

The neighbor had a 350 put in her 1955 Chev. It was a bolt in except for the little stuff. GMCs had their own trans, though, so I don't know if it will work. I'd probably rather go with the 366 as I haul with the truck still, but I will just have to look at my options.

 

[Tony in Mass.]

How about having a shop weld and machine the head you got? Or find another head out there-ebay?. Either is a lot easier than an engine swap. If that's all that wrong with a 55 year old machine.. get a valve job done while it is off, you might be very happy with it again.

 

[Bob]

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/StillAtWork.jpg">

All I can tell you is that the 1953 GMC truck in this photo has a 270 CID straight six and a 4-speed Muncie and it's bolt pattern is exactly the same as the transmissions in Chevy trucks of the era. (The TRANSMISSION bolt pattern, NOT the flywheel housing-to-engine bolt pattern.)

The 270 is built very close in design to a 261 Chevy, but few (if any) parts interchange. IIRC, the Chevy block is slightly shorter.

The '57 Chevy truck in the photo had a 261 six, and I replaced it with a Chevy 327 YEARS ago, keeping the Chevy/Muncie tranny in place.

 

[2x4]

292 should fit. stick with a 6 cyl. as they are built for pulling power whereas v-8 is built for speed. Once swapped a 283 in for a 261. v-8 would barely pull up out of the pit loaded. switched back to the 261 as soon as rebuilt. v-8's gain in speed over 261, maybe 5 mph.

 

[J3cub]

I bought my first semi truck in 1960.It was a 4 axel 14 wheeler, A 2 axel tractor and a 35 foot tandem axel Lufkin trailer. I could gross 60,ooo pounds gross. Texas did not allow 18 wheelers that grossed 80,000 pounds until 1962. I was hauling cotton seed and grain from West Texas up into Oklahoma. I was pulling the 60,000 pounds with a 283 small block Chevy. Put 140,000 miles on the little 283. I replaced the Chevy engine with a 389 Pontiac engine. I also farmed and we used several 389 Pontiacs on irrigation wells. The Munci 4 speed bolted right up to the Pontiac bell housing. ( I thought I had the fastest truck in the world). I think and G.M. engine with a standard trans bell housing would bolt up to any 4 speed or 3 speed G.M. trans.

 

[J3cub]

I should have said and trans of that time period.

 

[DeltaRed]

I agree,I think you would be happier with a big 6 over a small V8 for the low end torque.Therre is a reason most OTR semis use a big 6-TORQUE.But then again,a 350 is a fine engine for your old truck.I just last spring installed a newly rebuilt 350 into my '68 Chevy C50 .Runs like the proverbial "raped ape".

 

[RN]

Engine to bell housing bolt pattern Chevy was a circle, BOP/GMC truncated cone. Universal bolt pattern bell housings came out late 1970s? GMC trucks depending on models/years could have a Chevy engine or their own engine with the truncated cone engine bolt pattern-and the Pontiacs were a good swap, GMC 360 something V8 was same basic block as 389/400 Pontiac. Pontiac had speed equipment available in catalogs by engine, GMCs engines didn"t have much specific speed equipment available. Big Buicks used to one option for replacing the GMC 6 cylinders- engine bolt pattern to bell housing, slightly narrower heads to fit in engine bay and header sets that tucked as close as possible to block to help squeeze in to hot rod projects. Guy I used to work with had Buick in 1940 Ford pickup that looked like a "restored classic" as license plate indicated instead of hot rod. Illinois State police didn"t open hood and inspect it at time of issue of speeding ticket well over 100mph- motion for dismissal as judge must know restored "stock" 1940 engine wouldn"t do much better than 80 mph and slightly hot rodded flathead might make 100mph but not way over as the ticket said-like about 130. Judge asked if police inspected at the time, dismissed ticket when they said they hadn"t. Clerk advised judge said be careful now, police WILL inspect next time. 400 inch Buick does make more power than 250 or so inch flatead bored V8-100 replacement of V8-85. Collector plates issue for engine swaps other make not usually done- but body year is main thing they were going by and body modifications. RN

 

[Bob]

"Engine to bell housing bolt pattern Chevy was a circle, BOP/GMC truncated cone."

NOT in the in-line 6 270 GMC or the in-line 6 Chevy"s, 261, for example "cuz there was NO "flange" cast as part of the blck, like 292, for example, the older bellhousing matched the rear end shape of the block, more or less.

Here"s the engine side of a Chevy 235 or 261 bellhousing, GMC 261 is similar.

<img src = "http://i1326.photobucket.com/albums/u650/fastcar1953/IMG_20130828_202118_zps2c8e4853.jpg">