The Stovebolt Site Forums The Shop Area The HiPo Shop 283/302 small block installation

Have a possibility of replacing the 235 with an early small block, W/700R4 trans.
Who has experience with this installation?
I'm doing a cost/effort evaluation of the project. Looking for interference problems like distributor to firewall (move engine forward?), steering column, etc.
Any information would be appreciated.
The other option would be a late model 261 as a second choice.
This will be in a 51 2 ton, but most things will be the same as a smaller truck.

I have done a 1949 and am in the process of doing a 1952.
I used a motor mount kit from Chassis Engineering Inc. Item # CP-1160. $120.00
It is a well made kit with good instructions as to where to locate the mounts on AD frames to provide distributor clearance at the firewall.
I used the original rear cross member (which is bolted on and originally supported the torque tube ball) by moving it rearward until it lined up with the rear transmission mounting pad.
I cut out the middle of the center, riveted-on cross member, then fabricated lowering brackets out of plate steel to reattach the section back in 2 inches lower. I would recommend cutting the crossmember on a 90 degree angle. (My angled cuts in the photo caused the need to weld metal onto the cutout section for it to fit.)

Thanks Carl, really great information.
The 48 2 ton had no rear ctossmember to set the rear mount for the automatic on, so I made one. It is bolted to the frame so I can move it forward easily enough. The original cross member for the bell housing mounts (which go away with the automatic) just clears the trans housing/torque convertor by fractions.
I am already sure the 261 just won't be enough of a power increase. So the answer will be a 250hp 283 or 302.
I will probably have other questions, but thanks for now.

Jim, put a small block in my panel. Used the mounts from JCarter but was made by CPP and traded for a cross member. I'm running 700r4 behind the 305. As Carl mentioned the kits usually have instructions as to how far to go back, and the distance between mount holes center to center. I saved mine and can email them to you if you like.......Some places were a little close but I've had no problems and driven the panel a lot.

EDIT: Jim, I emailed you a sheet of how the mounts went in my 1/2 ton panel. May help? May not, but use as info.

If you have a 302 small block (a DZ engine # suffix) you can sell it for enough to cover your conversion---several times over.

If considering a 302, why not a 302 GMC six cylinder?
Then if so... it doesn’t take much over bore to make a 261 into a 302, and a 261 bolts in no trouble at all.

OK, sorry to muddy the field with the mention of the 302 (or the 307).
I was thinking of 225 - 250 Hp. Easily done in a 283. But not knowing the condition of the cylinders in this old block, an overbore could be required. Moving up to a 302 vs a 327 seemed more likely.

Can anyone tell me if the steering column has to be moved in a 2 ton to fit a small block? When I was looking for manifold and carb options for the 48 2 ton I found some had problems with the steering column, which I don't think they had in pickups.

Don't know about a 2 ton but the box DOES NOT have to be moved on a 1/2 ton if one uses a 265 exhaust manifold.

Thanks.
I was thinking about block hugging headers, but knowing that something stock fits is a big help.

For a 3100, the engine mount instructions from CPP measures from a specific rivet near the front of the frame to establish where the mounts are to be located.
The 2 ton will not be the same length, so if you can wait until I get my 3100 frame back from the powdercoater, I can measure from the front cab mount holes to where the engine mounts belong.
That should guarantee that the engine will fit ahead of the cab.

Yes, that would be helpful.

For mocking up engine swaps, I usually use a bare engine block and an empty transmission case for establishing the location of motor mounts, crossmembers, etc. Even with a set of heads attached with a couple of bolts to check firewall clearance, etc., it's a lot easier to maneuver than a complete assembly.
Jerry

The biggest obstacle with a small block in an AD is the distributor. I have enough room to fit my open hand between the big HEI distributor and the firewall with the CPP mount kit.

I don't you think a small displacement v8 will be all that and a bag of chips on a 2 ton truck, Can't seem it being worthwhile for all the work compared to what the 261 can do. So, I think a stroker 383 would be a better power plant unless you plan on driving the truck empty only. Piston crank kits are cheap and will turn a 350 small block into a torquey powerplant with the right camshaft. IMHO

Just stuff a tall block 366 in there and you'll have a real truck engine. 350's are like belly buttons- - - -everybody's got one, and most of them are pretty boring to look at!
Jerry

Your right , 350 small block is just like any other small block to look at. My point is if he is resigned to put a small block in his 2 ton, get as many cubes as he can so it won't be lethargic.

My son bought a 1959 Chevy 2 ton C 60 this summer. It has a
283 and a 5 speed transmission.

I went on the GM Heritage Center and found that the frame
width on the front of the frame for a 1959 3100 - 6600 to be 34"

The same dimension for the 1951 3100 - 6500 is 35"

It is raining now and will not have a chance to measure but
I will find out the distance between the 59 steering gear box/column
clearance tomorrow. Though there appears to be a lot of room
on the 59 2 ton. Jeffrey

Thanks Jeffrey, that will be useful.
Jerry, that's what I'm trying to avoid. I want this to be an engine update, not re engineer the whole truck by trial and error.. When I was asked about putting an LS1 into the 51 COE project I had a bare frame and bought the foam mockups, block, heads and auto trans to prove it couldn't be done w/o making a new frame.
People have done this, or at least attempted it, before. The beauty of forums like this is that people with experience and knowledge are willing to share it so other people they don't have to reinvent the wheel over and over again.
As far as power goes, the client isn't going to be happy until we have 327 with 300 - 325 HP, so I'm resigned to that. At least it will bolt up to the 700R4.

OK, I'm a little cranky this morning, sorry.
If the rear distributor is a problem, I can have the engine built with the front distributor option.
Does this solve any other problems? Can locating the block without concern for the distributor make any improvement on other clearances?
Because of the 700R4, the rear engine cross member and mounts will not used. Tripod mount - 2 front mounts and transmission tail mount. The rear cross member I made for the transmission is bolted to the frame so it can move forward or rear easily. I wouldn't have had to modify the firewall/floor to fit the transmission in if I could have moved the original engine a little forward.
The small block is shorter than the original engine so there should be lots of room to move the engine forward to clear the distributor unless the pan hits the front cross member. (modify the oil pan)
As I recall the cooling fan on the 283has a long spacer between it and the pulley to get it closer to the radiator, that can go if necessary.

Modify the bellhousing crossmember, but don't remove it altogether. It also serves as a brace for the rear spring pivots and there will be some nasty flexing of the frame if it's not there. A better way to handle the transmission clearance problem is to fabricate a bolt-in center section that drops a couple of inches to make room for the torque converter housing.
Jerry

I could have phrased that better. The bell housing cross member is not now nor would be later used For Mounts.
Right now the transmission clears it by fractions of an inch. moving the engine/transmission assembly forward would actually make it better.

The original bellhousing cross member added considerable stiffness to the frame at the rear spring hangers. With our without any mounts it it's a good idea to have a cross member at the front spring rear most hangers.

GMC 400 series didn't have the same cross member and engine mounts as the smaller trucks, instead they used a large U shaped channel iron bolted outside the frame just behind the spring hangers.
See attached pictures of this 400 series cross member adapted to a smaller 2 ton GMC. I can't find a picture of one as fit originally in the 400 series GMC.

I've been in your shoes many times- - - -dealing with a demanding customer who has no idea what he's asking for, or if the resulting project is going to do what he wants it to do. Putting a hotrod V8 in a situation more suitable for a low RPM high torque inline six is a really good example of that kind of thinking. It seems your guy would be better off with a 292 with a few torque-improving modifications than any other option, but explaining the facts of life to a customer with his mind already made up is an exercise in futility!
Jerry

Guy in facebook in the Chev GMC 47-54 forum has a 305cu in V6 just pulled out of his truck runs great $500. Not a bad way to go either IMHO

That's in interesting idea.
I believe, however , the decision has been made. The client is ordering a 325hp, 327 crate engine.

I hope he's got enough gears to keep it wound up all the time. That HP happens only at wide open throttle, high RPM, and the torque band is very narrow. He's putting a Kentucky Derby thoroughbred in a mule pulling contest!
Jerry

The customer is always right. Uninformed, hard-headed, stubborn yes, but still always right.
Good call on your part for having your client purchase the crate motor that HE wants. Its all on him now.

True about the power curve. It will probably put out 200 in the normal driving range, twice what he has now and all the truck needs anyway.

Build the drivetrain strong enough to survive when somebody winds it up and bang-shifts into the next higher gear with a heavy load onboard. A machinist friend had a piece of 4" driveshaft tubing hung up over his lathe with 3 full turns twisted into it after a driver revved up a 425 HP Caterpillar 3406 Diesel and sidestepped the clutch- - - - -with the fully-loaded rig buried up to the hubs in a muddy rice field! The shaft looked like an hourglass!
Jerry

OUCH!!!

The torque converter (non-locking) in front of the 700R4 should save the drive line from the worst of it.

Yep- - - - -that happened just a bit south of you, at Foster Farms in Livingston CA. in 1978. They grew their own rice for feeding the chickens they grew and processed. I was running a diesel shop in Merced at the time.
Jerry

I was born in Merced. Been to and through Livingston many times.
I still have Family in Snelling, Atwater, and Chowchilla.

Well, the customer is always right, that can be true, but sometimes a customer will go to a pro because he does not know, he expects info and he wants to learn... A 327 in that truck is indeed a funny idea, but maybe this customer wants a 327 because he had 1 in high school (in a Nova), or his parents' station wagon had 1 when he was a kid. Maybe someone needs to tell him that any small block can be made to look like a 327 (with the right stickers!), maybe he is the kind of guy who just does not know and who needs to hear about options, to hear that GM sells an excellent 383 crate engine that would suit him much better (if he wants a GM crate)!
Because the risk here is also a customer who ends up not happy and blaming the shop for not steering him in the right direction...

Didn't "Poor Richard's Almanac" have a few comments about somebody with more money than sense (to put it as charitably as possible)?

Something about being "soon parted"!
Jerry

I did not know we had any rice fields in the U.S. Very informative post so far.

It's really cool to say you have a 327 because it sounds Corvettey. It was called the "Mighty Mouse" motor.
It's also cool to say you have a 454 because it's a Big Block. A Rat Motor.

In eastern Arkansas and central California, the rice fields are so big they use crop duster planes to sow the seed. I was driving near the end of a plane's run one day out in California and got pelted with thousands of grains of rice when he pulled up for another pass. It was like a mini-hailstorm.
Jerry

They burn the rice stubble here in SE Mo. Nasty.

Hey Jim,
I just got done attaching the CPP engine mounts on the frame of my '52 3100.
I measured from the center of the front cab support bolt hole, to the center of the hole in the CPP mount. It is 31 inches.
The center-to-center measurement between the two CPP mounts is 19 inches. (That 19" is what CPP calls for in their instructions.)
These specs should put your small block right where you need it regardless of what series truck you have.
Carl