348 truck engine

[W Head]

I was at a swap meet and some one had a 348 truck engine long block for sale. There was not a timing chain cover and cast into the front of the block, behine the cover, was the word "truck". I have never seen this before and no I did not get the casting numbers. (wish I had) Everone I have spoke with tells me this was never done, but I saw it,"really I did". Has anyone ever seen this on a 348? :?

W Head

59 El Camino 348-3,2s
59 Impala 409-2,4s

[Bam59]

hi.. today i removed the paint off of the front pad and found the code to be T206H which is a 230hp 348 truck motor. the timing cover in on so can't help you with the word TRUCK. but what is the differance between a 230hp truck motor and a 250 hp pass. car motor :confused:
dam i lost 20 hp in 2 mins flat-------------must be a record :deal
thanks for any help

[ToddK]

The truck motor is like the marine 409, there is an added area of space in the top of the cylinder which increases the size of the combustion chamber and thus lowers compression and horsepower. Look in the lower right of this picture and you can see the "cut out" area that's added.

[Bam59]

so is that the only differance is the combustion chamber?
cam, pistons, heads .etc. are the same?
was hoping to put more hp. into motor, is this a bad idea?
motor is running very good, just thinking maybe more hp.
how much street hp. can one get from this kind of motor?

thanks

[Mr Goodwrench]

todd I think all 348's had the notch machined in the top of the cylinder (some had two) 409 pass blocks were the only ones that didnt have them. am I right guys????

[johnnyrod]

The 348 and 409 car blocks have no relief cuts. the truck ones all have it in the 409 and the 348. John

[Ronnie Russell]

Mr Goodwrench., You are correct, however I have not seen a block with 2(maybe 348 truck,,I am unfamiliar with those)

[fatride]

Mr Goodwrench is right, A true 348 truck block had two machined notches, all 348 passenger car blocks that I have seen had one notch.

[No409]

my 655 348 truck block has 1 valve relief

[Mr Goodwrench]

abrey can shed more light on this, I think the older 348 trucks had two, believe he called the carbon collectors, other than those I'll stand by my first post All 348's have at least one notch.

[Bam59]

hi,,, first sorry W- head for taking your post but maybe this will help you to.
what i'll do is put a bore scope in plug hole to see how many cut outs i have.
next pulled valve cover off of the pass. side of motor and got these numbers.
from the front,3764702 which i can not find in the casting part of this site.
middle of head GM-2,,rear F2360.
intake numbers are K1458 3732757 GM-3 which is a 58-61 250 hp 348 (i think)
so again i ask is the cut outs the only thing differant between the 230 250 hp. motors. is the rest the same? thanks for any help
p.s. still trying to get num's from the back of motor :bang

[Ronnie Russell]

Mike, To answer your original question, I would believe the differance between the 230hp and 250 hp would be compression ratio differance between pistons used in truck motors and pistons used in passenger car motors. Camshaft would also be a little different.

[Mr Goodwrench]

truck pistons are different, camshaft is same as 250-280 HP 348 and I think the 340 HP 409 but is retarded 4 degrees by use of a "truck" timing gears. curt harvey told me years ago you must be careful what timing set you use because of the 4 degree diff.

[Bam59]

ok,,now do i set the timing a 8 or 4 degrees?
i just had a bunch of the guys help me with the timing and set it at 8 degrees start,, full 34 degrees,, full open at 3200 r.p.m.'s and i thought it ran great. but tonight
reset it to 4 degrees and it may be a little crisper.
i should have never took the paint off the block:bang
thanks again and sorry for being a pest. but i have to know :brow
.

[Mr Goodwrench]

talking about cam timing, not ignition timing. either the crank or cam sprocket was made (dont know which) so it retarded the camshaft 4 degrees. dont ever feel like a pest, when you dont know something you ask, there is a great wealth of knowledge about these engines here from some very fine people. like I tell my students "there is no such thing as a dumb question"

[Bam59]

ok....i'll return it back to 8 degrees and just drive it.
thanks,,,,,and no more ?s on this matter :cheers

[348NUT]

Hey guys, This is what I believe to be true from my research on truck engines. The 58-61 blocks used in cars had one small relief cut in the blocks, this includes the 11.25 350hp blocks too! The blocks used in trucks had two large notches cut. From 62-65 they started using the #655 blocks and only one notch like the former car engines. to lower compression in these engines they switched from a standard car piston to a special shaped truck piston. I have never heard of a #655 block with two notches, but I'm no expert. They also used the #333 truck heads on the 348s and 409s alike from 62-65, as well as other heads. 409 car engines had NO notch, trucks had One and a special piston.
Bam, I'd check your compression, if it's in the 150#+ range you've got car pistons, if it's 120 or less you probably have truck pistons. I know this isn't for sure but it will either put your mind at ease or bum you out even more :rolleyes:
Hope this helps, NUT :)
p.s. I've never seen or heard of the word truck being cast into the block. Ya learn something everyday!

[Bam59]

hi,,,mr.348 nut did a compression test. first warm motor up pulled all plugs
opened and locked carb. wide open.
driver side. #1-145 pass.side #2-130
#3-145 #4-135
#5-135 #6-145
#7-150 #8-130
i'm no chevy gear head but if one of my harley's had 20 pounds differance
i'd be doing a top end.
should i put in a little oil in cyl. and retest ?
i do not have any popping from intake or ex. so i do not think it is valves.
i do not know what cam is in it, hyl.or solid. or anything about this motor i got it two years ago and it was running.
will it be ok to drive till spring then do a rebuild the winters are a good time for driveing here in the sunny south ?
the big problem is here know one knows what a "W" or 348 is, called two bigger rebuild shops and was told NO WAY.

now i know why the south lost the war

[Ronnie Russell]

C'mon Mike, Dont blame the whole south because of a few poor rebuild shops. I must be overlooking something, You earlier said your motor was running real good. Its a low compression truck motor , probably got plenty of miles on it. I would not scrap the motor because of those compression readings. Keep on driving and maybe you will run across a passenger car motor in the meantime. You ask if it will be ok to drive til spring. Are there some symtoms I overlooked? If it is horsepower increase you want, it will take a rebuild with some good parts. There has got to be a competant shop somewhere in your area. Good luck

[Bam59]

thanks Ronnie,,,yes it does run good at least i think so, it don't miss a beat
pulls good (truck)it should. i think i'm reading to much into things still trying to get this car stuff. just finding out what i have here and with all the help here i am. sorry about the remark to the great state of texas. but i'm not kidding about the repair shops here.

[Daddys409Belair]

I hope I speak for all other Texans - APOLOGY ACCEPTED! :)

[OldTruckNut]

Mike, don't feel too bad about your engine rebuild shops. I'm sure it wouldn't be hard to find alot of machine shops around here that have never even seen(or possibly even heard of) a W motor let alone worked on one.

[348NUT]

Sorry, I've been away a few days. With those compressions I'm sure you have some car parts in there. that said My stuff says H is a 250hp car engine where did you get the idea it is a 230hp? Do you know the casting number on the block and what year the engine is? 20lb diff. is marginal but if it runs good I wouldn't worry about it. NUT

p.s. I think I see where you got confused on the suffix code, The T is for Tonawanda engine plant. The H is the code for 250hp.

I'd try oil in the 130lb cylinders just to see if it is rings? Good luck!

[Bam59]

well i have allways said i'm a harley man and cars are not my strong point.
now i'm mad :cuss because i feel like a b-head, :bang but did get a lot of good info.
i have not yet got the codes off the back of motor, waitting on a bore scope.
but on the bright side i got 20 more hp in one reply :D
i looked at a lot of numbers that night on the mortec site. heads, intake, old dist. ex-manifolds. now do i have this right the one head num. is 3764702 which i think :dunno is 1960 truck, now for the same ? what is the differance between car and truck heads if any.
thanks to all for the help AGAIN

[Ronnie Russell]

Mike,, You can retrieve the casting no. with modeling clay. You can get a hand down there even if you cant see it. Makes a good imprint. Recovered one not long ago from a 62 that I couldnt see.

[SS425HP]

Never thought of that, before. What a good tip.

Thanks

Fred

[Bungy]

Ronnie, I never would have thought of that in a million years. It's so simple, it's genius! How many times have I tried to stick my head between a valve cover and the firewall? :bang
Another way that I've gotton the numbers off the back is with and old rear view mirror and a flashlight.

[Bam59]

is the num. facing up or to the rear? got play doe.

[jim_ss409]

I think the casting numbers face UP, on the ledge where the bell housing bolts on, on the drivers side. They would be facing us on the botom left corner of the attached picture. Right about where there's a little bit of orange paint left.

[bobs409]

Ronnie, buddy ol' pal. :D May I add this great tip to our Tips/Tricks page? I'll give you all the credit of course! :brow

Mike,, You can retrieve the casting no. with modeling clay. You can get a hand down there even if you cant see it. Makes a good imprint. Recovered one not long ago from a 62 that I couldnt see.

[SteveD409]

Bam-Truck heads have recessed valves which creates a little 'chamber', which in turn, lowers the compression a bit. Also, the valves usually have rotators. But for some reason the truck heads (at least the 333's) have larger ports.
SteveD