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time to build the 454 for the 68 burb

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55Willy

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It's a 1973 ls4 truck motor. 270 horse 390 torque built nov 72.
Oval port heads but my castings don't show up " 353046 " i think the 5 might be an 8 after looking at other similar year castings.

This was all rebuild less then a year ago and now i'm pulling it out of the 73 so it can be freshed up for the 68. I'm gonna do a cam, intake and carb swap on it along with headers.

As i'v had nothing but small blocks before so I know nothing about the performance of a oval vs rectangle port head, open vs closed chambers?
also what kinda cam selection for it. I will be running hydro brakes so vaccuum isn't a concern. So if any of you have any imput please share :laugh:
 
I have basically the same engine/heads
Engine is 399289 with date code of K2872 (11/28/72)
Heads are 353049 withe date code of L672 (12/06/72)
Heads are oval, open design. Maybe your last digit is a "9" instead of a "6".

I've not had this engine running, but have been told the heads are very good for low rpm torque, and not so much for high rpm.

That's about all I've learned so far. I bought it about 2 yrs ago and haven't done anything with it yet. Now I'm getting the itch to use is to replace my tired 6.2 diesel.

I'll be watching your build thread if you do one. Interested in costs mostly at this point.
So if anybody had rough estimate to rebuild a 454, post up.
 
this motor was rebuilt 3000 miles ago. I'm just gonna do an Edelbrock Air Gap intake with a 770 holley "avenger" series carb (truck or street) so i'm just looking for cam selection with the compression ratio I have ( which I don't know what it is)
 
well, i found out the LS4 has 8.5 to 1 so I need a good low end grunt cam for it.

going in the 68 burb in front of a th400 with a 30" tall tire. any recommendations?
 
There is no 046 head that I know of. Check your numbers again.
You prolly have either:
049 They are large oval port. 049s and 781s are the best oval port BBC heads. Will support over 500 HP easy with no work. Your early 454 would have most likely came stock with these heads. But who knows what happend over the years or what GM put on it 1973 was the start of smog motors.
As far as Cam: you can go from mild to wild depending on how you want the motor to run

045: These are peanut port heads. Ports start out oval then reduce size and get round. Low RPM grunt truck/smog heads. Not much good over 4500 RPM Use a low RPM RV type cam.

I woud not run rectangle port on a truck unless you want to make a full race machine out of it.

You really need to positivly ID the heads so you can pick the right cam
 
55Willy said:
they are the 049's
Click to expand...

:thumb::thumb: You have a good set of heads. You can do pretty much anything you want with your engine.
049= open chamber heads. IIRC 113cc chamber. They are a very good flowing BBC head. Depending on cam/pistons work well for both low end and up on the top too.
Re your asking about open Vs closed chambers. Open chambers have larger combustion chambers than closed chambers. Closed chambers are smaller chambers CC and higher compression heads.
But you can run domed pistons in open chamber to raise the compression ratio. cant run much of a dome in closed chamber
As for a cam for your engine not sure. Been a long time since I have played around with a BBC dont know what is out there. But call Comp Cams they have a good selection of BBC cams and will help you get what you want.
 
whats the max lift for stock valve springs?

also I won't be running hydro boost brakes as I wont be running power steering.
 
Can't you still run hydro boost brakes without running P/S? I would think you just won't be plumbing in a gear box is all. :dunno: This is assuming you wanted to run hydro boost rather than standard power assist brakes.
 
never thought of that. not sure if i have the room since my rack and pinion goes right past the motor mount (where the ps pump would be) hhhmm gonna have to drop the motor in just to check the clearances.
 
My 462 is 9.45 to 1 , I'm using a performer RPM Q-Jet intake, Comp Magnum roller rockers (they fit under stock valve covers) and it doesnt seem to over do the Idle.
 
i'm stuck with 8.5 to 1 compression unless someone is giving away pistons, rings and bearings,lol this thing doesn't have 3K miles on it.

i just want to wake the motor up a little bit.
 
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