If you're doing other work to the motor, to make it breath better, 3" will be fine.
I've got 3" from the collectors back on a 5.2, and I'm happy with it.
Sure, theoretically something smaller might be optimal, but getting a custom 2-5/8" exhaust was not where I want to spend my $$... if I keep working the 5.2 to a 390, or pick up a 5.9 for a 408 project, I already have the exhaust.

 

PO on my truck had 3" exhaust on the 5.2 and I switched that to 2.5" I was happier with the 2.5" IMO, although I didn't have the 3" on my 5.9

 

I'm running single 3" with no cat and a hooker maximum flow muffler. I'm happy with it. Oh and I've got short tube headers.

 

What do you mean happier with 2.5"? Sound wise or power wise?

 

Power wise mostly, wasn't a huge difference. Sound I'm not sure because I switched mufflers when I changed diameter.

 

Well now that the Fall semester is over, I'm itching to get back at this build!!!
Just took a ride to the local Race engine shop with pops, (a long, loyal customer), and talked to the head engine builder there, he told me come back with a cam you want, bring in the heads and well get those things done up. As these are factory heads, they only have 4000 miles on them and are from S&J engines.
Long story short, anyone have any recomendations on a cam? Looking for some good low-end grunt, but without a doubt don't want to sacrifice top end performance at all.

I'm especially looking into the Comp Cams 20-745-9 recommended by redneck_ram.
http://www.compperformancegroupstore...Category_Code=

Any input is greatly appreciated!
Gonna probably take off those heads sometime tonight!

 

Nice thread. Read the whole thing actually. Looking forward to the end results.


But if I ever went to a 360, would the HS 1.7 Rockers bolt right up out of my 318?

 

I'm looking forward to seeing this build too!

Chilly,
Yeah, your 1.7 rockers will bolt right up. the 318 and the 360 use the same heads.

 

^Sweet, thanks man.


And I can't wait to start doing this performance stuff to my truck. It'll be awhile but still. Gotta take care of my 3 more inches of lift and gears.


Then I'll start the good stuff.

 

Well I finally got some money saved up from after the holidays, and decided it was time to start the build. So I took off the heads the other day and took them down to the shop. I told my machinist what cam I wanted to run with and he said he'd take care of them from there. This is the cam & specs. (Comp Cams 20-746-9 http://www.compcams.com/Company/CC/c...?csid=661&sb=2 )

He was really amazed at how clean they looked because of the low miles on the heads (4000 miles) I inquired about infact doing larger valves on the heads but he didn't really agree with me because of the cost to do it compared to the little power gain I would receive out of doing that. (He's a good family friend looking out for me and not trying to scam me).
Just today he called me back with some updates that the one head looks like cylinder #7 (of course) exhaust valve is smoked and also the valve guides aren't looking too good. So, I'm either in search of new heads or repairing these but the only thing is, if I repair these I'm still running the risk of crapy stock heads vulnerable to being cracked again. I gotta give him a call again tomorrow to sort things out.


I also inquired with running HS 1.7 adjustable roller rockers and he said with that cam I might be running the risk of hitting the cylinder to the bottom of the cylinder, can anyone confirm that with me?
I'll put up some pictures of the teardown.