Exhaust layout - 1994 K2500 7.4L

[Chessie]

Greetings -

I was poking around under my truck today as I have been thinking about upgrading the exhaust system. I was surprised to find out that my catalytic converter is located on the backside of my muffler. Is this the stock setup?

Thanks,

-c

[Boomyal]

Yep! That 454 generates so much heat that you'd burn the cat out if the muffler backed up exhaust into it.

If you want the best upgrade for your boat anchor, check out the Gale Banks Power Pack. It isn't the cheapest but it's the best. You put it on and forget about it. Other systems keep burning out the exhaust gaskets. Forget using a "cat Back system" near total waste of money. I'll bet your 454 almost goes flat above 3000 rpm. With the Banks System it'll keep pulling strong right past redline. You can also slap in a 180 deg thermostat and bump your initial advance by 4 degrees. It's about as much as you can do for a motor that only has 7.9:1 compression.

http://www.galebanksengineering.com/chevy.cfm

[Chessie]

Boomyal -

Thanks for the information. Makes a lot of sense now that you mention it. I checked out the Banks Power Pack. It looks like a nice set up. I have been thinking about changing the intake system as well, so this would kill two birds with one stone. You mentioned advancing the timing 4 degrees. Others have mentioned advancing the timing. Question for you, are you familiar with any of the chips availalbe for the '94 454? Are they worth while? Any favorites? I'm really not looking to turn this Suburban into a go-fast truck so much as I would really like to pick up some power for towing my boat.

Again, thanks for all of the good information.

[Boomyal]

Chessie,
What do you mean by "changing the intake system"? The Banks system includes provisions for better intake flow. A full tuned header/exaust system will give a hefty improvement in your pulling power but here are only limited improvements that you can acheive as long as those ol pistons are just slapin in the air.

I've made some preliminary inquiries about changing the cylinder heads to ones with smaller combustion chambers. Object, to increase the compression into the mid to higher 8's. So far no one has been able to identify smaller cc heads that would work on the '94. If you could up the compression you could get a better cam as well. Stay under 9 to 1 and you could still run regular gas. Like you, I would like to get a little more umph for my 8.5 (towing) to 11 mpg (hwy). Those would be doable upgrades without having to pull the motor. You could consider one of these:

http://www.superchargers4less.com/whipple/gm454.htm

I think that chips are of limited value for this motor.

I would like to find a knowledgable and active site for BBC's as this one is for Ford Windsor motors. Then we'd get some answers.

http://www.network54.com/Hide/Forum/119417?it=0

[Chessie]

Hi Boomyal -

I was saying that the Banks system includes a new air intake system. I was considering something like a K&N FIPKS. That wouldn't be necessary with the Banks system.

I'm starting to understand that many of the relatively quick and inexpensive mods availalbe to other motors just aren't really gonna net much for this motor.

Thanks for the new URLs. Something else for me to check out and learn a bit from.

-c