Don Terrill’s Speed-Talk

Was all set on upgrading my 5.3 to a 6.0 so I can tow...and be a little more fun to drive this thing is anemic for anything other than just point a-b
WOuld be done right meaning machined, cant wrap my head around the junkyard worn out build thing. I want this to go a solid 100k+

Read about turning the 5.3 into a 383 with a 4" crank, got my attention. What is the valve size limit of the 5.3 bore?

This has to pass Ca smog (no sniffer just visual/ck for codes), idle smooth just as it does now. Keeping it whisper quiet too

Id use GM heads, just put a good valve job and port them, nothing fancy just want big low end tq. Cant use a great exh so hp is of no concern


Pros/cons of ea? 6.0 blocks out here are a fortune but will wait for the right one. I could go either way I guess.

Cam around 208/210ish??

Should I stroke this 5.3, port maybe add 2.00 valves?

Or go 6.0

Anyone??? I know some of you guys know. I twont be a max hp deal but want big tq from this.

cv67 wrote: ↑Mon Jan 27, 2020 9:21 pm Should I stroke this 5.3, port maybe add 2.00 valves?

Or go 6.0

Anyone??? I know some of you guys know. I twont be a max hp deal but want big tq from this.

-wouldn't 6.0L be the simple, easy way to go?
-But....everybody....i mean everybody... i know that has anything to do with a 6 litre...bitches about fuel consumption

Well the 383 will definitely make more torque, like 25lbs or so...all else being equal. I'd use a set of 706 or 862 castings, put a 2.00 valve in them with a nice valve job and let it eat.

Your going to have the money in crank and pistons with the 383, but on the other hand..6.0's usually aren't cheap to buy. Depending on if you are Gen III or Gen IV, you might consider using a stock LS3 or LS2 cam. 204-211 117 ish .550ish lift on the LS3, .525ish lift on the LS2.

This brings up the question that I have wondered about for some time. The 6.0L has always had a 'reputation' for being hard on fuel- is this justified? Or more so the operators foot. I was talked out of doing a sbc1 383 years ago because the machinist felt at the track it was of little value over a 350- but I had a chance to revisit a few years ago for truck duty and I would say with no data back up that it was worth the crank and pistons and the truck barely shifts gears going up steep grades compared to previous.

dfarr67 wrote: ↑Tue Jan 28, 2020 10:27 am This brings up the question that I have wondered about for some time. The 6.0L has always had a 'reputation' for being hard on fuel- is this justified? Or more so the operators foot. I was talked out of doing a sbc1 383 years ago because the machinist felt at the track it was of little value over a 350- but I had a chance to revisit a few years ago for truck duty and I would say with no data back up that it was worth the crank and pistons and the truck barely shifts gears going up steep grades compared to previous.

I think a lot of that came from what they mostly came in. 2500HD truck with a behemoth turd 4L80E, big everything...add towing and its a wrap.

The 6.0's also had that problem with piston slap when cold. Worse if using synthetic oil. And yes, everybody bitched about the mileage.

Piston slap is certainly not exclusive to 6.0's. With enough miles, they all have it.

i could care less about mpg its a heavy truck. it only avgs 12 around town im fine with it. Never understood guys complaining about that?!
If it gets 9 and does the job Im a happy camper


Whatever works best for the $ is what Ill do. If i can stuff a 2.00 valve in this bore then maybe.

Either way-


dfarr stroking is the best thing youll ever do for $ vs tq on the street. Find another machinist, Id never build the same CI again no matter what
That bigger arm is what most guys hope for when the cam their stock engine up or do heads etc. That torque does it.

CGT wrote: ↑Tue Jan 28, 2020 10:33 am I think a lot of that came from what they mostly came in. 2500HD truck with a behemoth turd 4L80E, big everything...add towing and its a wrap.

I think there's a lot of truth in this. Often 3.73 or 4.10 rear end, and a big 14 bolt full floater at that, 2pc driveshaft, power robbing 4L80E, and a truck that's 1000+ lbs heavier than a half ton in the same cab/bed configuration and you are doing all you can to drag mileage down.

The 5.3 would be more convenient unless a better deal ona 6.0 popped up

Any recomendations on a rotating assy?

Suppose I could get 2.00 valves in or ck out the new AFR as cast heads they are cheap maybe clean em up a bit?

cv67 wrote: ↑Fri Feb 07, 2020 3:50 pm The 5.3 would be more convenient unless a better deal ona 6.0 popped up

Any recomendations on a rotating assy?

Suppose I could get 2.00 valves in or ck out the new AFR as cast heads they are cheap maybe clean em up a bit?

Or just use any 241, 243 or 799 With 2.00 valves in them already and a better port with to start with than any stock 706 or 862 casting. It would be better than the 2005-2007 5.3 L33 engine if you did it with the 383 cubic inches instead. Should be better gas mileage and close in torque to a 6.0