270 GMC engine rebuild tips wanted

[akguy34]

I have been working on rebuilding a 270 GMC engine to drop into my 42 GMC CCKW, I’m not sticking to strictly stock on my engine but I’m not buying the latest and greatest for it either. I have a stripped 270 engine and a LOT of extra parts I’m just trying to figure out what would be a good combo. For example I have 8 oil filter canisters and about 4-5 air filters and about 3-4 maybe 5 intake/exhaust manifolds two kinds of valve covers and two kinds of oil pans.
My ultimate goal is to build a dump bed truck with a plow to haul gravel and firewood in the summer and plow snow in the winter
First I have the three size oil filter canisters I would like to hear opinions on the three sizes: ease of getting replacement filters? is the biggest the best or with the oil pressures would a smaller filter more efficiently?
Second, air filters I have the pancake filters that attach directly to the carb and one that attaches to the firewall and runs a hose to the carb is there any real difference? What are the pros and cons of keeping the system an oil bath verses converting one to a dry filter?
Third the current oil pan and pump are the normal depth version, I also have 2 engines with deep well pumps and pans, is it worth the trouble converting it to a deep well? Or even just replacing the pan with a deep well (my thought is more oil in the pan to cool and a place for the gunk to settle were a normal depth pump would not be constantly picking up the dregs in the bottom)?

Thank you for any opinions or ideas,
Joshua Curtis

 

[NDT]

The deep sump pan was developed because the oil pickup on the shallow pan would suck air on steep grades. As far as oil filters, you cant beat the Military Senior Filter and the C-31 element that goes in it. The correct air filter is the oil bath one that mounts on top of the carb. The clamp type was the early set up which was not durable, the later bolt on type is bulletproof.

I did some mild porting on the head of my 270 when I rebuilt it, not sure if it helped a lot.


If you keep your truck mostly stock looking, it will retain greater value in the collector market.


Good luck and post pictures of your Jimmy!

 

[akguy34]

well the collector value has already been destroyed by the previes owner after he chopped 4 feet off the back and removed one set of axles. heres a link to the pics

http://s1191.photobucket.com/user/akguy34/library/1942 GMC

 

[m1010plowboy]

Those cabs are beautiful. I'd give my left wheel nut for one like that. Thank you for not chopping it up more and jam a big block in there, with a blower and a green intake sitting just high enough above the hood for the butterflies to work...and lowered with a 3" chopped top with stacks coming through the cab corners and out the back at a 45 degree angle 3 feet above the cab and big ol' white walls stuffed in the fenders.

I've always wondered what my 302's would be like with some port and polish. Back in the day a buddy of mine would take a grinder to his heads, exhaust and intake. He'd just widen the openings and try to make the ports match along with making them smooth. The castings are always a little rough and he just thought it made sense that the holes should match and be shiny. His little 318's would embarrass the Camaro guys so bad he earned the nik name Gizmo.

Not sure where Salcha is so it'd help if you add the state or province or confederate Salcha is a part of.

Very lucky to have that truck, a little chopped all ready so a little less guilt adding running boards, I like it.

 

[ducer]

Those are low rpm engines so a port match and polish would kill low end torque and may cause fuel mixture issues such as puddling in the intake ports. With low rpm engines you need the fuel and air mixture to tumble a little so you get good fuel atomization and mix. Instead go through and clean any casting flash and trapped casting sand from your ports. If the engine regularly sees over 5,000 rpm then port and polish is in order. When I was young I ported, matched and polished a set of buick v6 heads for my buddys jeep. At 3,200 rpm and above it ran great and pulled like a train but below that no power and wierd missfires. I talked to another buddy of mine and he said put a set of cleaned up stock heads back on and all will be ok. I did and all was right with the world.

I hope this helps,
Denny

 

[rosco]

I balanced a GM 302 & an 264 International. It does wonders to smooth things out, when your pulling that long hill.

 

[NDT]

Looking at the pics, that is a really nice CCKW. My '42 had the back of the frame cut off as well, it is not hard to fix, just need a donor truck. But for ease of maneuvering around, your set up is perfect.

 

[retired wrench]

If you are going to push snow you sure dont want to add that second axel back on. Ive seen 6 bys stuck in a foot of snow. Brother in law had to burn the spare tire to keep from freezing to death in Korea when he got stuck in the snow.