Iron Vortec head info on YouTube

[larrylarry]

Maybe you’ve seen this already but I just found this on YouTube. PISS-CUTTER Performance. There’s some good info on iron Vortec’s. When I was working on mine about 8 years ago I didn’t think to check on YouTube, probably wasn’t as much info as there is now. Anyhow for anyone who is looking for info on iron Vortec’s here’s your answers.

 

[biker]

He does some neat stuff. Lives in south west Ontario, I was just through there for work this week. I've traded some messages with him, nice guy.

 

[krabben1]

My iron vortecs move my 6000lb laden truck pretty good.Stock from 96.

 

[sandlapper]

a great deal of info on web about iron vortec L31 head limitations has become obsolete; newer info, newer techniques.
a few simple steps *** will easily net most street vortec motors the needed lift capability (without cutting guides/spring seats):

*ensure stem seals are properly seated on guides --- GM Powertrain L31 shop manual shows a spec.

http://www.kohlerpower.com/onlinecatalog/pdf/tp6104.pdf

*do a proper ghetto grind on bottoms of vortec retainers.

*install a common set of "Z28" springs with deleted inner flat damper (NO damper).

 

[1980RS]

Easiest for me was getting the spring and seal cutter, put them in a drill and cut the guides down. Dirt cheap and east to do. The other way is to use .100 extra long valves as most GM valves I found are junk anyway and I won't use them. The guy on PISS-CUTTER performance does have some good videos.

 

[frank5s]

Beehive springs +.050 locks and +.050 retainers worked for me.

 

[sandlapper]

In some cases, when using OE self-align aka guided rocker arms --- and while using +50 locks and +50 retainers causes the Vortec's taller OE extended stem tips to recede back so far into the retainers that the rockers' rails may be kissing the retainers --- not good --- be advised.

method in p#4 works for most street cams and is cheapest way to skin that cat.

 

[larrylarry]

Some pics of my Vortec’s.
One thing I found is the chambers on mine where 62cc. I didn’t want to go to far on grinding out material. I cleaned up under the valve seats & streamlined the valve guides on the intakes. Cleaned up casting flash in the runners an ruff up the runner walls & took off some material on the short side turns.Cleaned up the exhaust valve guides & smoothed the chambers & port matched the heads to the intake. Polished the back side of all the valves. Comp Cam retainers for LS1 beehive springs & Comp Cam self aligning 1.5 roller tip rockers & new thick walled pushrods. Wished I could of had these flowed but didn’t. I did dimple the chamber walls a bit but decided not to go any farther.

 

[biker]

Nice work, thanks for sharing. Sorry if I missed it elsewhere, but what's the rest of the engine combo? I'm doing the vortec heads for a 350 soon and always looking for tips.

 

[larrylarry]

Nice work, thanks for sharing. Sorry if I missed it elsewhere, but what's the rest of the engine combo? I'm doing the vortec heads for a 350 soon and always looking for tips.

I ordered them from Summit, there are the 062’s. I pulled the rocker arm studs using washers & a nut. Bought one of those rocker stud alinement tools for screw in studs. Somehow I got a couple of studs not inline with the others, leaning towards the valve a dergree or two. So be aware if you use the same alinement tool. First Let Me Say I’m not a professional at porting!!! but I did a boatload of homework before I started. I didn’t have a air grinder at the time so I used my rotozip. A Dremel tool takes to long & won’t have the reach you’ll need. Ended up buying an air grinder and a couple of 1/4 x 6” rotary files & a few 1/4 x 2 1/2” files. I’ve seen those porting kits that are rolls of sand paper. There good for polishing not for a full port job. Rotary files cut or grind cast iron pretty fast so you have to be careful. You can’t be forceful, heavy handed etc. Just light touches moving side to side. The roof or top of the runners don’t need any work. The short side bend & the floor or bottom of the runners require most of the grinding & on Vortec’s you don’t need to remove very much. Don’t polish the runners, leave them a rough surface. You can polish the chambers. I did use the Dremel for this, used some thick rubber disc with grit infused in the rubber, worked great.
Enough of that, porting.
Engine is a 350 bored 40 over, sadly it’s a 2 bolt main with ARP bolts. I was using the original 1978 crankshaft but worried about it’s age and bought a new Eagle cast crank. Wasn’t planning on spinning a 2 bolt main block really fast. 6” SCAT rods which let me use lighter DSS forged pistons. Howard’s roller cam, 266/270 [email protected] 213/217 lift .485/495 110 LC I wanted a cam that started sooner in the rpm range. It comes on cam about 3300 rpm’s, hits pretty hard but it does fall off about 5800 rpm’s. That’s about 130 mph in 4th gear, good enough for me. Lunati roller lifters. 750 Eddy carb on a Eddy Performer intake for Vortec heads 2116. An a regular no frills HEI distributor. 700r4 transmission & 3.42‘s in the rear.