Technical Chrysler 354 Build Thread!!!

[D-Russ]

EDIT: Go to the last page to see the latest update.

I just picked up my 354 Saturday and I've taken an rough inventory of what I got.

When I bought the motor (sight unseen) one of the selling points was that it came with 7 new .040 pistons.

I talked to a buddy that's a Ross dealer and he said they could make the 8th one for me for much less than the cost of a complete set. So that was one of the deciding factors.

When I got it all home I took a closer look and discovered that the pistons are .040 Speed Pro #H660CP – which are for a Chevy 327.

The old pistons that are attached to the rods (motor was disassembled) seem fit the current cylinders, but I didn't want to force the rings into the bores.

So here's my question – Has anyone ever heard of using 4 inch bore Chevy small block pistons in a 354 Chrysler? At a glance, the diameter looks pretty close, but the wrist pins are clearly in different locations. Perhaps .125 off.

So did I get taken?

P.S. I also posted this inquiry on the HEMI Tech Piston thread, but it's buried at the end so I don't think it will be seen by many folks.

[JeffreyJames]

Sucker.

[Ebbsspeed]

Originally Posted by D-Russ

When I bought the motor (sight unseen) one of the selling points was that came with 7 new .040 pistons.

Well, you did get 7 new pistons, right? Did he ever say if they were for a Hemi?

[D-Russ]

The stock bore is 3.9375, so is perhaps boring it to whatever 4.00 inches plus .040 is a possibility?

[scootermcrad]

Hmmm.... I would think there's a bunch of reasons NOT to run them, but everytime I say something like that an old-timer comes a long and says something to the effect of, "back in the day this is what everyone did", clearly proving I know very little... HAHA!

Congrats on getting the 354 Dave!

Maybe you can convert your Hemi into a SBC?

Just thought of something else... Aren't wrist pins different as well? You may ALSO have the wrong rods? Did he say it ran before he took it apart?

[Ruiner]

Pistons don't know what motor they're intended for...with that said, measure the wrist pin height, rod length and compare that to the factory deck height numbers...also be aware that valve reliefs may need to be cut into the pistons, but that's not a major problem...I'm planning on running 455 Pontiac pistons in a 361 Dodge big block with 440 Dodge rods, they're essentially the same bore but almost an inch shorter in wrist pin height, lighter and with the 440 rods I wind up with higher compression...it's a win-win...

[Ebbsspeed]

If they are .040 over for a stock 4" bore, you'll be close to a .100 overbore on the 354, which might be too much. I think I'd buy new pistons before taking a block that far without a good reason. If you do, sonic check first. The 1/8 inch pin height difference is going to play hell with your compression, whether it's on the plus or minus side. A stock 354 piston has a dome on it, which this particular SBC piston does not. The H660CP is a flat top hypereutectic piston, so if the pin location is lower than the stock hemi it might work, but pay attention to the edge of the piston, because you may have it kissing the outside edge of the chamber. If the pin location is higher, then you'll end up with really low compression, because you'll not have the dome that a standard hemi piston does, and you'll also be lower in the bore. Might work if you're running a blower, but I'd never stick a blower on top of hypereutectic pistons.

Your best bet is to call the guy and give him a piece of your mind for IMPLYING that the pistons were for a hemi, then have your Ross dealer buddy get you a set that are correct for your application.

[D-Russ]

I just sent the guy who sold me the lot an email:

I have a couple of questions for you though. The 7 pistons that came with the motor had 354 Hemi .040 written on the box in marker, but the actual label on the box says that the pistons are for a 327 Chevy. Did you perhaps put the 354 pistons into a Chevy box, or are you suggesting that I can run the 327 Chevy pistons in the 354 with the appropriate overbore? Or perhaps I got the incorrect box of pistons from your stash?

Upon visual inspection, the diameter between the old and new pistons is very close, but the Chevy pistons are slightly shorter and the wrist pin location is about 1/8 inch off.

Please advise.

I'll post his response when/if I get one.

[scootermcrad]

Post a picture of the pistons, Dave.

[D-Russ]

Originally Posted by Ebbsspeed

If they are .040 over for a stock 4" bore, you'll be close to a .100 overbore on the 354, which might be too much. I think I'd buy new pistons before taking a block that far without a good reason. If you do, sonic check first. The 1/8 inch pin height difference is going to play hell with your compression, whether it's on the plus or minus side. A stock 354 piston has a dome on it, which the SBC most likely does not. The H660CP is a flat top hypereutectic piston, so if the pin location is lower than the stock hemi it might work, but pay attention to the edge of the piston, because you may have it kissing the outside edge of the chamber. If the pin location is higher, then you'll end up with really low compression, because you'll not have the dome that a standard hemi piston does, but you'll also be lower in the bore. Might work if you're running a blower, but I'd never stick a blower on top of hypereutectic pistons.

Your best bet is to call the guy and give him a piece of your mind for IMPLYING that the pistons were for a hemi, then have your Ross dealer buddy get you a set that are correct for your application.

Yep, the "Chevy" pistons are flat top.

[Tom S. in Tn.]

I'd venture a guess, assuming these are flat top pistons, and say they could have been an off the shelf item for a stroker, possibly using a 392 crankshaft.

What kind of rods? Check pin height and rod dimensions.

4.040 would be .102~3 over.
I had a 354 made 390 that was made using a 392 crank, and I can not recall at this moment, but the crank was turned to fit off the shelf M/T rods for either a Ford or Pontiac, and custom Venolia pistons. Tom S. in Tn.

[D-Russ]

Originally Posted by Tom S. in Tn.

I'd venture a guess, assuming these are flat top pistons, and say they could have been an off the shelf item for a stroker, possibly using a 392 crankshaft.

What kind of rods? Check pin height and rod dimensions.

.040 was a common over bore for a 389~390" stroker.
I had a 354 made 390 that was made using a 392 crank, and I can not recall at this moment, but the crank was turned to fit off the shelf M/T rods for either a Ford or Pontiac, and custom Venolia pistons. Tom S. in Tn.

You're in middle Tennessee and you play with hemis, so you may know the guy I bought the stuff from. He's in Lebanon, mostly a 426 guy, and has a small collection of 60s and 70s hemi cars. I don't want to post his name, but do you know him? Trust him?

[sgmhemi]

I'd check with Bob at Hot Heads Research and Racing. He's a good guy and will answer your questions. There is also a tech forum for questions regarding early hemi stuff on his website. I got my Ross blower pistons thru Bob a couple of years ago.

[Ruiner]

The absolute biggest concern aside from deck/valve clearance with using those pistons is assuring that you have the correct bore size for running hypereutectic pistons...just because they fit doesn't mean the bore clearances are correct, and you could end up with some major damage once the motor gets up to temp...

[Ebbsspeed]

Originally Posted by Tom S. in Tn.

.040 was a common over bore for a 389~390" stroker.

If you're using the correct pistons it is. If you're starting with 4" bore 327 SBC pistons, you first have to bore the 354 block .0625 to get to the STOCK 327 bore. Add another .040 bore for the oversize that these pistons are and you're getting pretty close to Thinwall City, which is just a honing stones throw from Breakthrough Lake.

[D-Russ]

The seller already responded to me which is a good sign. Here's his response:

The box was only used for the pistons to store them in.The pistons should be for the 354. I am glad the motor finally made it home.I am solid Mopar so there has never been Chevy parts in my shop...LOL

If you need anything let me know.


I responded back asking for the piston manufacturer, part number and application. We'll see.

[bobss396]

Originally Posted by D-Russ

The seller already responded to me which is a good sign. Here's his response:

The box was only used for the pistons to store them in.The pistons should be for the 354. I am glad the motor finally made it home.I am solid Mopar so there has never been Chevy parts in my shop...LOL

If you need anything let me know.

I responded back asking for the piston manufacturer, part number and application. We'll see.

Yes, baseline what you have before doing any machining, etc. What do the pistons measure up as, just curious. Can you "borrow" a 354 piston to match up the features on the set of 7?

Bob

[scootermcrad]

Fwew! Well that's good news!

[Tom S. in Tn.]

Originally Posted by Ebbsspeed

If you're using the correct pistons it is. If you're starting with 4" bore 327 SBC pistons, you first have to bore the 354 block .0625 to get to the STOCK 327 bore. Add another .040 bore for the oversize that these pistons are and you're getting pretty close to Thinwall City, which is just a honing stones throw from Breakthrough Lake.

I saw this after I re-read. See my edit. Everyone is posting much faster than me.
I can only think of a couple people in Tennessee with any Chrysler parts. One has quit and I think I saw an ad recently where he was liquidating. The other is still quite active. I've trusted both in the past, but without any names, I have no way of knowing.
Tom S. in Tn.

[Ebbsspeed]

Post a picture of the pistons you have, if you could.