Torque Plates

[Forzfed]

I think I finally found a good engine builder since Earl won't move to Canada!

My buddy has a factory Plymouth GTX 426 hemi 4 spd car.  He took it to a local guy that just started a machine shop to go through the motor that was suppose to have a fresh rebuild.  He found a few issues with it.  He noticed that the rings weren't sealing in certain locations in the bore and those locations lined up with the studs in the head.  He came to the conclusion that however did the cylinders did not use the bolts or studs that were suppose to be on the heads on the torque plate.  He also likes to put all the head bolts under tension to see if they are even and if not tensions them to all the same value prior to install.

Sounds good to me.  What do you think, Earl?

[Steve Wood]

I'm not Earl, but torque plates should be torqued down to the same specs as the heads will be torqued down

[earlbrown]

Ideally, you use the same fasteners you're going to use and an old head gasket that's the same style you're going to use, and torque them to the same spec you're going to use.   Make sure the mains are torqued up as well.

If you really want to get anal (giggidy), torque up the motor mounts too.


If DADV is your thing, circulate hot water through the block while honing and adjust your clearances appropriately.


I like to leave the block in the honing machine overnight and check the final sizes. Based on my personal experience, blocks draw up 1/2 thou when they get back to room temp.



Funny you should mention that too. I noticed a few years ago that Buick V6 torque plates have gone THROUGH THE ROOF, and they're not even available to buy most of the time.       I was talking about setting up to do a production run on torque plates and wondering how long it would take to hit my break even point.


  Which reminds me, the main thing I needed to check on was if a plate will fit in a flat rate box.

[Forzfed]

Nice!    Good info, Earl.  So, I think I have myself a new machinist!  He sent my buddy a vid of him loading the bearings and checking the tension.  He said that even though the bolts are torque to spec doesn't necessarily mean they have the right tension on them and this could lead to the bolts coming loose over time.

[wmsonta]

 has a factory Plymouth GTX 426 hemi 4 spd car.   

Jeez...

[Forzfed]

It's a very rare combo.  I forget what he said but very few came with the 4 spd.

[wmsonta]

It's a very rare combo.

Everything about it is rare. GTX was rare because of cost. It was considered a luxury performance car. In the Plymouth line, think more than a Sport Fury. A base GTX was somewhere around a third more than a base Road Runner.

The Hemi was extremely rare because of cost and insurance. With all the street racing I did, I only saw one compete. At the track in those days, the Hemi's had their own classes. they could only compete against each other. They had a weight sanction against them in the pro classes.

  I forget what he said but very few came with the 4 spd.

A 4spd was an additional cost option in at least the last 3 yrs. I do not believe I have ever seen one, 69 thru 71.

[gusszgs]

I personally always like the GTX, way cool and the ‘70 Runner. My brother had a ‘70 RR 383 Magnum
That being said, the one car that gave the Mopar guys fits in those day was the STG 1 GS Buick lol
In stock form against each other, the Buick would outrun a Hemi

[Forzfed]

I remember reading an old magazine that had an article from back in the day of a Hemi Cuda vs Buick GS.  They said the Cuda couldn't hook so they put some sticky tires on it and left the factory bias ply tires on the Buick.  And the GS still beat it.  The Buick 455 weighs as much as a small block, so I imagine there would be a huge weight difference between it and the Hemi.

[Steve Wood]

Huge  might be an understatement

[earlbrown]

Yuge, perhaps?   

[wmsonta]

I am too smart to get involved w/brand loyalty on a brand specific forum.
I do, however, have a somewhat comprehensive list of engine weights. Helpful when building from scratch. Probably never use the Pratt&Whitney weights, but-
-a 455 Buick is approx 20# lighter than a 350 Buick
-25# more than a '60's sbc
-5# more than a 500 Cad
-140# less than an early Hemi.

No info on a 426 Hemi.

I do not doubt the article or that it happened. Having went though that era, I won't try to explain it. Pure Stock and on street rubber available when those cars were new, I would have bet good money an SC/Rambler would have beat both. 'Scambler' Ramblers were the cheapest/lightest niche muscle cars ($3000)made. At their rated hp, there was no insurance penalty.

[Forzfed]

One of my buddy's is building a 455, I actually picked some parts up for him.  He was the one that told me the short block 455 weighs the same as a short block Buick 350.  I cannot confirm or deny this.

I have an old Magazine where they took a Chevelle LS6 454 and ran it against a stock GN in the 1/4 in freezing conditions.  They put ET streets and race fuel in the Chevelle and left the GN bone stock.  The Chevelle won but the GN gave it a close race.  Again, they should have put race fuel and sticky tires on the GN.

[wmsonta]

One of my buddy's is building a 455, I actually picked some parts up for him.  He was the one that told me the short block 455 weighs the same as a short block Buick 350.  I cannot confirm or deny this. 

I have never weighed them. Externally they are identical. The 455 has over a half inch larger bore and some amount less webbing. My information shows a 455 @ 600# and a 350 @ 620 as installed. I have a large list, nothing verified.
 

I have an old Magazine where they took a Chevelle LS6 454 and ran it against a stock GN in the 1/4 in freezing conditions.  They put ET streets and race fuel in the Chevelle and left the GN bone stock.  The Chevelle won but the GN gave it a close race.  Again, they should have put race fuel and sticky tires on the GN.

I own a stock GN (slighty larger rear tires) and am better acquainted with a '70 LS6 than most. OEM, as delivered, I would bet my car would win. With any reasonable  amount of traction, my car would easily lose.

The LS6 as produced, w/oem distributor would require better gas than was available at the pump from about 1973 on. They were advertised @ 11.5 compression and would 'pour' above 11.

About 3 mos. after the LS6 became available, a dealership engaged me to help one of their mechanics 'blueprint' and dyno an LS6 crate motor. GM chose to over rate the LS6 instead of rating it at 425 hp. The 425 was a BS deal manufacturer's used for insurance purposes. Some 425 hp motors were ridiculously underrated. At least 3 made 500+. At 21, I could not have driven an LS6 Chevelle (450 hp) if given to me. A 425 hp car would have required high risk insurance for the duration of the note and this would have had to be brokered thru the bank or dealer.

An LS6 was a nice car and was expensive. Not as expensive as a GTX or a GSX. I drove them, rode in them, worked on them and sold aftermarket parts for them. The first one I tuned, would wipe the oem tires out in 3rd gear. If you allowed it to peg the tach, it would probably take 1 1/2 seconds to get under steam again.

Oh yeah, that crate motor dyno'ed 434 gross.

[Scoobum]

A few vids for the Mopar fans from my channel. Dan Kellers Roadrunner and Keven Pelletiers Procharged Coronet. Dans car runs 6.4 in the 1/8th and Kevins runs 5's...it's a monster. We all bracket race together with these boys in Nostalgia Class.

Dans Roadrunner walkaround...https://www.youtube.com/watch?v=1BwiPoRlpxo

Kevins RT...https://www.youtube.com/watch?v=LlHbFS7-924

The boys runnin' heads up...https://www.youtube.com/watch?v=doorvW76RWs