1973 Chevy 3/4 454 - 496 build + more

[RPOZ11]

1973 Chevy 3/4 454 - 496 build + more

After some thought... considering my current vehicle stock, It came to me that I needed a parts mover, tow vehicle, and completely reliable truck to finish off the rest of my stable.

Thus, my 73 is getting the once over mechanically front to back.

It's a complete #'s matching motor & transmission set-up; so once pulled, it will be sealed up and placed in the corner of the garage for safe keeping!

I will be installing a 496 stroker kit; a 4.250 scat crank, a set of scat 6.385 7/16" cap screw rods, and a set of .030 over KB Forged Pistons.

I just picked up a Gear Vendor unit for the TH400.

Will be rebuilding the rear axle last.

Now, I am looking for some comments on a set of Doug Thorley Tri-Y Headers for this BBC application.
I have a set, but I am 50-50 on keeping the stock cast iron manifolds in place for this truck.
Does anyone have any pros or cons on fit, installations, any adjustments to factory parts surrounding these headers????

I am also considering searching out someone who is making aluminum reproduction radiators. I thought I had seen someone somwhere who was offering these with original appearing GM style Harrison side tanks.

Also, with the Gear Vendor install, anyone have any suggestions regarding these????

I will post as progress comes along...

Thanx guys!

[1Ton]

I say use headers let that heart pump!!

[RPOZ11]

I like it.

I am concerned about the fit of those, and maybe alt/PS/A-C bracket issues and as well maybe the clearancing of the sgifter linkage for a column shift automatic.

[RPOZ11]

Well, I received part of my Gear Vendor today.

The Adapter casting wasn't machined enough to my liking so I am going down to my friend's machine shop to Jig & square this thing up, check it all out, and do some minor fixes to the machining flaws that exist as received.

I'll post our results as they come in.

If this process works out, I could effectively have yours repaired if you so choose to use this brand.

[RPOZ11]

Gear Vendor Unit :

[RPOZ11]

Got the Heads back today from the cylinder head shop.

These are 781 heads, 2.19 / 1.88 valves, Hard Seats, New Guides, Valves, Seals, everything new!

Gotta get the bottom end balanced next!

[RPOZ11]

Originally Posted by 1Ton

I say use headers let that heart pump!!

OK, well I picked another set of the BBC Thorley Smog Tri-Y's.
They were in Excellent shape and a great price.

Now, I left these with my friend and we are going to massage these out to flow even more than they are staright from Thorley, as they made them.

Should be 2 weeks before I get them back.

I will post up what we did to them then!

[RPOZ11]

Also picked up a 3:21.1 14-Bolt rear axle.

I think I have finally found my freeway flyer gears!

Got this axle drum to drum.

I am very lucky to find this gear set!

[RPOZ11]

Time sometimes I think is against me.

I spend more than time that I have available.

Here is the Block in the Prep stage work:



The 4.250 Crank after being fixed and Balanced!
This was a Brand New out of the Box crankshaft and it desperately needed Mallory to fix it!
At least it's Balanced now!





Still waiting to do the Exhaust system.

Should be taking the Truck in at the end of this month for this to be made and installed.

[67shortie]

Great build

I am doing the same thing to my Chevelle soon, buying SCAT parts as well. I wonder why that crank took so much mallory to get balanced? Is that a externally ballanced crank that you wanted internally ballanced?

Looking good

[77BBGMC]

I'm going to be building a stroked BBC as well. I have the block and a good set of 781 heads, now I'm in the process of saving some $$ for the build. Out of curiosity what cam are you going with?

[retro69]

That is the first I have ever heard of a SCAT crank being bad, I have heard of some eagles being off a little. I am in the process of having a 496 built buy local performance shop that dynos. The owner says he only uses SCAT and swears by them. I choose the 049 heads for my build. I am curious about the gear vender setup and install. If you post gotchas on the setup it would be nice.

[RPOZ11]

Originally Posted by retro69

That is the first I have ever heard of a SCAT crank being bad, I have heard of some eagles being off a little. I am in the process of having a 496 built buy local performance shop that dynos. The owner says he only uses SCAT and swears by them. I choose the 049 heads for my build. I am curious about the gear vender setup and install. If you post gotchas on the setup it would be nice.

I cant explain the issues with this crank other than it must be in the casting processes that this crank was run in.

Does SCAT spin these prior to packaging to determine the bulk of cranks from a "said" casting pour to determine consistencies/irregularities???

I dont know.

This is how it was straight out of the sealed box we opened from SCAT.

The results are what you see in the Mallory installed to Balance this thing back to a usable piece.

049 HEADS

I really wanted to use my set of 049 heads that I have here.

Being this is just a tow motor and my 1st 496 build, I had these 781 Heads laying around and these 781 Heads are nearly identical to the 049 ones.

Beings that I was going to do the work to them that I intended to, whether 049 or 781, they werent stock castings amymore once the port work, bigger valves installed, and seats as well, even the backside of the valve area cast-iron was massaged.

They arent stock in comparison anymore once all this work was done.

So I saved my 049's and used the 781's in this build.

GV set-up

Ill post them as soon as we start this part of it.

I have a brand new wiring harness, adapter, and a rebuilt unit as seen above.

Gotta build this exhaust system and factor in the GV added length for adding the X-OVER pipe.

The Doug Thorley Tri-Y Headers were cut and we added a larger 2-1/2 Collector to get this to breathe more.

It takes so long to do this right the first time.

Sorry for the long timeline.

[RPOZ11]

Also, I posted a wanted ad but havent gotten any results so I am going to add it to my build thread here in hopes someone might have what I need here:

http://67-72chevytrucks.com/vboard/c...ct=3767&cat=19


I need the Bracket and a correct GM used working EGR unit for my 73 Chevy truck.
looks like the one in this picture below:



OR, If you have the very same intake with the EGR that I need as shown, PM me as I might take it.

[turbo350]

You have a great looking truck! As far as headers go they win hands down for exhaust flow but also depends on what kind of sound you want. With a full exhaust and some nice say, hemi turbo mufflers, your truck will have a nice powerful sound but not obnoxious. I recall reading an article in Car Craft several years ago where they did a test with some hogged out exhaust manifolds and ran them against some headers. The headers had better flow but not by much in that contest. The cost of getting manifolds to flow better may be more than most guys would care to spend considering you get better results in general from headers right out of the box.

Good luck with your build!

[RPOZ11]

Originally Posted by RPOZ11

Also, I posted a wanted ad but havent gotten any results so I am going to add it to my build thread here in hopes someone might have what I need here:

http://67-72chevytrucks.com/vboard/c...ct=3767&cat=19


I need the Bracket and a correct GM used working EGR unit for my 73 Chevy truck.
looks like the one in this picture below:



OR, If you have the very same intake with the EGR that I need as shown, PM me as I might take it.

TTT

Anyone got one of these setups???

I am still looking for this EGR and bracket + bolt factorty setup.

HELP....

[RPOZ11]

"Out of curiosity what cam are you going with? "

I was relying on my motor guy on this more than my choosing one.

I typically stay around 500" to 520" on lift.

I will share a small suggestion of his thoughts ...

"we want to reduce a small bit of cylinder pressure from idle, so adding a little bit more duration should slow down any detonation and or pinging."

He is very High on using the EGR valve system to help with the same issues as well as our current gas available here in California.

With sooo much torque, he wants this motor to work inside the available octanes we use as well as the California gas additives incorporated into our gas.

Slowing down the temperatures off of idle.

[RPOZ11]

Originally Posted by 77BBGMC

I'm going to be building a stroked BBC as well. I have the block and a good set of 781 heads, now I'm in the process of saving some $$ for the build. Out of curiosity what cam are you going with?

Camshaft #'s request.

I need to get the cam card for this as we had this camshaft made specifically for this application.

I dont think it is too much different than the available cams out but they did add more duration on the intake side to support the larger displacement.

I have to get that card as we need it to dial in the QuadraJet & HEI unit I have.

Ill get back to you on this!

[89muscletruck]

ouch!

[RPOZ11]

496 is Finally completed ; minus distributor, carb and new small parts.

The push rods arrived in the wrong length so we went bought another set.

Going to rebuild a later model Quadrajet and include an electric choke in the vacuum pod's place.
Probably bush the throttle shafts, tweak it up to handle the larger cubic inches, recolor it and adjust it after breakin.

Small list of stuff to target now:
Radiator
New motor mounts
Belts
Aluminum water pump
Hoses
Starter
Temp Gauges
Misc other things


Hope we start the R & R in 3 weeks.

[RPOZ11]

Picked up my motor yesterday.

(valve covers are on backwards only for the purpose of sealing it up and for transport-FYI)

Man, this is getting expensive!

Dropped it off over at my friend's shop, where we will be doing the swap at.

Next door they have a DYNO.

It was optioned to me to break this thing in on the DYNO and tweak it for power.

Gotta think about this.

The camshaft was off on the dial in. We ended up advancing it 3*. The duration was bumped up a little on this cam to adjust for the extra cubic inches.

Took a core QuadraJet with the electronic choke in for rebuild. Do it up all new, bush the shafts, etc etc.

Also took in a DAVIS "DUI" HEI I had that was used on a prior 454 I had and will reset the advance to match up with this 496. I think that one was originally set up a 22* @ 3400 RPM's.

So, next I have to steal some pulley's, A/C brackets, and more form a core 73 454 I have lying over here, and start assembling the front of the motor.

Im just fortunate to have a spare motor and parts truck to take from while I still drive the truck before we start the swap.

Gonna purchase some Urethane motor/trans mounts.

Slow movin' but progress is being made.

[BillyBlaze]

schweet!

[West Texas Z]

looking good!

[RPOZ11]

Took off some small parts for assembly onto the new 496.

Everything will be bead blasted and repainted then reinstalled.

A/C Unit + Bracketry:

[RPOZ11]

Alternator Assembly :