PDA

View Full Version : Doing Head Gaskets 350 Vortec, Cheap/Free Mods?



TheBigMortboski
03-20-2012, 10:45 AM
I've got to do head gaskets on the 98 GMC 1/2 Ton. Its losing coolant at a rapid pace, white smoke out the exhausts, yadda yadda yadda. Sigh.

While I'm in there, is there anything I can do that is cheap or free to maybe get it to run a bit better? I'm getting a sweetheart deal on the machine work (it pays to know low people in high places), so I don't want to say, "while you're in there, how about a free port and polish?"

Also, I don't have my Haynes manual with me, are the stock rocker arms on these engines roller?

And I'm also doing exhaust donuts (one of them has apparently evaporated into thin air), would it be worthwhile to clean up the inside of the manifolds?

SUBURBIAN
03-20-2012, 11:10 AM
Stock rockers are long slot self-aligning stamped 1.5 ratio...no roller tip, no roller fulcrum.

TheBigMortboski
03-20-2012, 05:42 PM
Lame. And Trickflow has some roller 1.6 ratio rockers. Must... resist... spending... more... money...

SUBURBIAN
03-21-2012, 09:26 AM
Must...make...sure...they're...self-aligining...:D

TheBigMortboski
03-21-2012, 09:47 AM
Good call. The only self-aligning roller rockers they have through Summit are Crower. They're only 1.5 ratio, but they're over $500! Eek.

SUBURBIAN
03-21-2012, 03:29 PM
Summit just showed me 37 options for 350" gen 1 sbc, full roller rocker, self-aligning....

BlacK20
03-21-2012, 03:43 PM
Good call. The only self-aligning roller rockers they have through Summit are Crower. They're only 1.5 ratio, but they're over $500! Eek.

http://www.scorpioncheckout.com/SearchResults.asp?Cat=85

I have these in 1.5:1 version, love them, very budget friendly.

TheBigMortboski
03-21-2012, 05:33 PM
Summit just showed me 37 options for 350" gen 1 sbc, full roller rocker, self-aligning....

Man, I suck at the internet.

I still shouldn't spend the money, but its good info to have if/when I do a real rebuild on it.

SUBURBIAN
03-22-2012, 07:42 PM
I really think the jury is still out noticeable power gins from a rocker arm swap anyways. Unless you're building a max effort purpose built engine, the stamped GM pieces are adequate. I run them on an old school smallblock that sees 6500+ all the time.

TheBigMortboski
03-22-2012, 08:13 PM
Yeah, I equate roller rockers and the like to, say, cold air intakes. Just by adding them you aren't going to turn it into a racecar, but anytime you can reduce resistance, it adds up.

And if you went to a 1.6 ratio it would be like a cam swap, for lift anyway.

SUBURBIAN
03-22-2012, 08:34 PM
Maybe it lowers oil temp and engine temp from less friction. Maybe parasitic loss is decreased enough to produce a bit more power. Maybe it equates to a .1 or so on the track.

TheBigMortboski
03-22-2012, 08:40 PM
True enough. However, if I am to build a performance vehicle, it won't be a 4000lb+ four-wheel-drive truck.

That requires a different vehicle. And that requires a job that is a bit more steady than construction is right now.

Jon4x4
03-22-2012, 08:44 PM
man i can just drive there and pick up the rockers for mine haha

Doober
03-25-2012, 01:20 PM
You can also blend the throat to the valve seat area, just about every stock SBC head has a ridge there from casting, and it shrouds the valves. That will make sure each throat is nearly identical, and you may get a few hp to boot :) I took a chance and did a little blending around the valve guides and the short radius of the exhaust ports, but mine is also a TBI 383 with a cam.
http://s302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/?start=all
http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/DSC06557.jpg
http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/DSC06577.jpg

http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/DSC06580.jpg
http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/DSC06582.jpg

http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/DSC06585.jpghttp://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/Vortecs/DSC06578.jpg

You can see the throat blending done in the last two pictures. TBI heads are much worse in this area. These are the heads I originally had on the engine.
http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/DSC05167.jpg
http://i302.photobucket.com/albums/nn117/Skinner12082/92%20Sierra/383/DSC05697.jpg

ChevyLs1z
04-23-2012, 07:19 PM
You could get your heads milled...raise in compression for more power...dont know if it would mess with the computer though.