Inliners International Forums General Discussion Engines Newbie 250 to 292 advice/help

I'm kind of new here. Met some of you at the Jack Halton - Mid Atlantic Meet in PA a few weeks ago. I was going to put a V8 in my StepVan until then. I was talked out of it luckily

I have the 1972 13.5 foot Aluminum Step Van, see Jack Halton - Mid Atlantic Meet pictures. I have a well run 250 in it currently which runs good, except for a loud tapping in the head, and have a used 292 sitting on my garage floor ready to be rebuilt and tweaked. I bought the Leo S. book and have been through it a few times. Seems most of the info pertains to HP gains and racing. I'd like to get as much torque as possible out of my 292 so it hauls my big heavy Step Van around easily and later a 10-12 foot enclosed trailer. Maybe do a burn out or two and shoot some flames out the back, LOL. I've changed the 4.11 rear ring and pinion to a 3.42 and an Auburn Posi unit. It's really not as peppy as when i had the 4.11 R/P in it, so really need the Torque upgrade. I plan to go from the 3 speed on the tree to a 700R4. I've got a 1985 Caprice 700R4, wondering if it will bolt right up or does it need an adapter or shaft changes?

So far from my limited experience it seems I need to get:

flat top pistons, need to do a .60 over on the block, looking for 9 or 10:1 compression right?

head work somewhere, or a lump port maybe, shave the head a bit

Stovebolt split manifold

hotter cam, but not sure which one

Offy intake, 3X1 will fit better then the 4 barrel because of the dog house issues again and looks neater, The Van needs more neatness

seems I have to do something about the passenger motor mount, is this available aftermarket or do I have to make it?

Anything else or am I totally wrong with the info I have collected from the book and the search button?

Still waiting for conformation on my membership in the club, check still hasen't cleared.

Thanks in advance,

Step vans came with 292s so a mount should not be a problem if you can find one. I would suggest looking at a 70s GM truck parts book; you may luck out and a 292 could use the same mounts only on different set of holes in the frame. The 700r4 will bolt up to a 292 or 250. The driveline will likely need to be cut. Make sure the flexplate you use has the correct holes to mount the converter. If you really plan on hauling with the truck and going to an OD trans, I would go back to the 4:11s.

Don't get too carried away with a cam. As you want torque, you do not need a bunch of duration and you likely will not be turning more than 5000 rpm so pick the cam accordingly. You need to get some expert advise on the head; that is where the big money comes in. The valves and flow rate need to match the cam and depending on who you talk or listen to, you may not even need to cut the "dividers" out of the head or add lumps. The carb choice is yours, but the more there are the harder it is make the linkages work and tune.

I would keep the compression low enough to run 87 octane. You are going to push a lot of air and needing to go to 90 or 93 will cost a whole bunch more.

Just opinions..........

Thanks for the info Bruce!

I planned to shorten the driveshaft. What's deal with the flexplate, what should I be looking for? I went with the 3.42 gears because I thought a V8 was in my future. It's not an option now, and I'd hate to rip into the rear again which is why I want more cubes...hence the 250 to 292 swap with a .60 overbore and other recommended power enhancements. Should I be looking at a T-5 instead of the 700r4 because of my new rear ratio and possible towing need?

While looking at the clifford website I see they have a kit that might work for me:

"Fittment: All Chevy 292 cid. Description: Our Clifford rebuild kit includes cast aluminum pistons (0.030" or 0.060" overbore), chrome rings, a Fel Pro gasket set, Clevite Bearings (main and rods are 0.010" undersized), Clifford 264H camshaft, lifters, high lift springs, retainers, valve locks, and hardened pushrods. Please note piston size, along with main and rod bearing sizes with your order by checking the boxes. All cam bearings are standard size. Do not forget to zero deck your block!!!"

Will this cam be too much for my truck/needs if I keep the head stock except for a basic cleaning?

I wanted to go with the 4 barrel carb instead of the 3x1, but it looks like it may not fit with my doghouse style in the step-van. Does anyone have a mesurement from the side linkage to the mounting surface on the head when using the Clifford 4 barrel intake and holly carb?

I may have to deal with the higher octane in order to get more torque from what I have read and heard from the vendors so far :-( I gathered that LP Pistons with zero decked block and some head work will bump me into medium grade gas but it should be a happy medium of torque and mileage. Is this recomendation off base?

Thanks for the input Bruce,

mooney

The factory flex plates are usually drilled only to match up to the convertor the vehicle was built with. I believe the 700R4 uses the same bolt pattern as a TH350 while a Powerglide is different. If you are going with an aftermarket piece, they are usually drilled for both.

I would take a 700R4 over the T-5, especially if pulling a trailer. Only problen with the 700 is a fairly large gap between first and second, but it is a given with the 700 or 4L60.

I could not find the specs for the Clifford Cam. You need something with torque at very low rpm and if it maxs out at 4500rpm you would still Be OK. Have Clifford send the specs on their diffent cams and check out Comp cams. Also you may want to check into the Offy manifold as it is supposed to be better for the street. It would be worthwhile for you to talk to Tom Langdon at Stovebolt Engine Co. He can probably give you best advice you can get on the combo and application...

You may want to take a look at http://www.Ultradyne.com They have some good cams that run from idle to 5000-5500 Lift ranges 468 to 530
with a 112 lobe seperation Which should still give you vacum for
power brakes.

Did any of the 292 engines come with a 700R4? If not then it would be a challenge to get parts to match.
Our local transmission man does the work for the trucks at the local paper mill. He likes using the THM-350 in work trucks. The only modifications he does is put a Towing Style Shift Kit and a Transmission cooler on them.
If you have $300 you can also get an RV style Torque Converter. The important thing is to get the biggest Transmission cooler you can get. That will keep your Transmission happy while moving that heavy Step-Van.

What was the last year of the 292?
Also what vehicle were they in?
Did we ever have an EFI 250 or 292 here in the states?

MBHD