hi guys, my 85 Pontiac trans am has a v-belt setup, the car has a 355 sbc, i decided to swap from v belt to serpentine, i took all the accessories off of a 350 5.7 tpi engine, everything went smoothly, i just went to put the belt on and noticed that i dont have clearance to get the belt between the crankshaft pulley and the water pump pulley? this makes no sense why is this happening? im so confused? do you think the previous owner lied to me and this is not a 355 sbc? also what are my options solution wise?

 

A 350 has the same crank-to-WP spacing as any other small block Chevy.

The .030" overbore doesn't affect that.

Loosen the bolts on one of the pulleys enough to slip the belt through.

 

Can you get a decent picture of just how close they are?
The factory setup isn't that close at all.

 

What the heck

 

 

so yeah these are the pics of the situation, makes no sense to me lol

 

I sure don't remember them being that close at all

 

Did you change the water pump?

 

Yes I changed the water pump, everything I used came off the donor engine. It was all fine on the donor engine, I know because it had the belt on and that was the first thing I took off, and it came off no problem

 

could be a crank pulley off a truck, some of them are slightly larger to speed up all the accessories for better cooling and more juice from the alternator. or maybe it's a larger underdriven water pump pulley to slow it down a bit.. or maybe it's a mismatched combination of an overdriven crank pulley and an underdriven water pump pulley.

if the block had the mains line bored when the engine was built that will push the crank up a bit- but only a few thousandths of an inch at most.

 

Yeah that's TOO close, the belt is going to rub itself...

Almost looks like the water pump mounting is too low on the block.

This a 70s block?

 

The truck serp stuff uses a different pulley depth.

 

All the accessories came off a 1989 pontiac firebird GTA, 5.7 350.

Sofakingdom, now that you mention it I do recall the PO saying it was a 70's block, does that mean anything?

 

Just that the QC was SOOOOOPER SLOPPY back then, and all sorts of things escaped from the factory done wrong... the single most common being, the starter bolt hole pattern drilled in the wrong place. Next most common, the lifter bores being drilled either in the wrong place or at the wrong angle, such that the lifters don't point at the cam, and the block EATS cams. And another, that the bell housing dowel pin holes are drilled in the wrong place, such that the transmission isn't centered on the crank, and it EATS pump bushings. Or, the one where one or more of the 3 oil gallery passages drilled halfway through the block from the front, don't meet up square with the other half drilled from the back, and because of the restriction where the holes partly block each other off, the front half of the motor (either the bearings, or the left lifters, or the right lifters, or maybe more than one of those) is starved for oil.

Notice a common thread here, wherein holes are drilled in the wrong place?

Wouldn't surprise me one bit if the WP pattern was drilled wrong. Back in the day, it didn't matter, because the pulleys were a bit smaller anyway. I've never noticed that happening, but it wouldn't surprise me at all if it DID happen, seeing as how about EVERY OTHER hole got screwed up and they used the block anyway, over periods of DECADES, without fixing the messed up tooling.

What's the block casting number and date?

 

I'd think the easiest way to fix this is run a "street" underdrive aftermarket crank pulley.

 

Yeah, that'd be easier than moving the bolt holes up 1/16" or whatever.

 

Well I live in Ontario canada and throughout this whole project its been a nightmare finding the parts I need, can anyone recommend a underdrive pulley that will fit my application or a pulley I can get off another block that will work, I wanna get this over with asap I hate having my car in a no start state lol, my buddy said that I should try to lossen the water pump bolts and hold it up while I retighten it , he said it might get me a 1/16 of an inch and maybe that would be enough to get the belt through, I'm going to try that later on but I doubt it will make any real difference .

Worst case ill just order somthing from jegs or summit, but please someone with some good wisedom link me up to something that will work ,

Thanks so much for all the comments so far.

 

I think I have a used aluminum pulley setup if it comes to that and are interested.

 

I just want a crank pulley that works atm, but Ill keep it in mind in case it does get to that, thanks

 

What are the diameters of the pulleys?

If one pulley is non-stock, might as well replace it, instead of replacing a stock one and having an even further "service parts" issue.

 

have you got another waterpump you can use to mock up and see if it makes any difference?

 

hey guys so what i did was loosen the water pump bolts, then i used a thick screw driver to shim and support the water pump while i tightened the bolts, and it gave me a little more space, then i squeezed the belt through and its on now, so hopefully it stays like that, but i definitely have to get a smaller crank pulley at some point because i don't feel like its sound to keep it like that, but at least i can get the car moving now, as i side note, the center crank pulley bolt, is 65 pounds torque okay on that? and the smaller ones i did 20 pounds, i read that around here on the forum in a couple places so that what i did lol. hopefully its okay!

 

Did you use the water pump from the serpentine accessory setup too?

Factory moved things around in subtle ways on the later reverse-rotation (serpentine) pumps. You can tell the difference because the WP pulley threads are metric instead of SAE.

 

Glad you got it worked out!

 

Ever get the block casting # and date?

 

Where would the block casting number and date be? Would it be easy to see with engine in car?

 

[sarcasm]It's in the most convenient and accessible place they could put it, right out in the open. [/sarcasm]



Top of bell housing flange, behind the driver's side head.

This block is a 3851509. 400 2-bolt.

The date code is on that little raised oval place to the right of the main casting # in the pic, next to the feature that looks like a clock. (for good reason) Not legible in the photo. It will look something like E156. The letter is the month, the last number is the last number of the year in which it was cast, and the numbers in the middle are the date. In that example, it was the Eth month (the 5th, May) of a year ending in 6 (if your block is for example a 3970010, typical 70s block, that would have been 1976), 15th day: May 15 1976. It typically takes around 2 months for a block to get from casting to vehicle assembly.

The one in the photo was cast sometime in 73 if memory serves. Had The Lifter Bore Problem but the starter bolt holes and BH dowels seem to have been OK.

 

Quite a convenient place lol, well I can try to take a peek but I doubt ill see anything. Thanks for the pic and casting number date info,

 

Its definitely in your best interest to look it up. Get a telescopic mirror and light it up good back there with a flashlight. You may even have to scrub the grime off with a wire brush first, but do it. You never know, you may still be running the original 305 as there is no physical difference between the two motors. More than one 305 has been passed off as a 350! Even your phone might capture a decent enough pic if you can finagle it back there.
Good luck!

 

Hey guys just wanted to update you all on the situation, so i finally got all the serpentine accessories on, and cranked the engine all went well, nothing flew off as i feared would happen, so that was a great relief. i wanted to just thank all who posted comments. i tired to find the casting number on the block but there are way to many things in the way to get a clear view, ill try and do that during another project, perhaps when my Holley sniper comes in this june.

Thanks! and SOLVED!

 

the pulley bolt pattern is also different, and reverse rotation water pumps don't have the mounting provisions on them for the V belt alternator and PS pump.