confab

My car never idled right since I bought it. Finally got back to it. Checked everything, Had leaky injectors (They were stock) Replaced with a set from FIC. (Thanks John!)

It helped, but still had a miss. Did a compression test. Failed on one cylinder and was low on another. Low mileage .030 over reman. Failed injector probably wiped the rings. (A squirt of oil and the compression jumps right back to 145) I noticed loose valve guides. Filled the ports with solvent and the valves leak a little. It was just frustrating me everywhere.

Due to circumstances beyond my control I didn't get to work on it for a year, it just sat. I love the car so I'm going to fix it. Rather than rebuild the heads I have, I was going to go with a new pair of Vortec 12558060's and a TPI intake to match, a set of rings and maybe a cam.

This is a combination GM never offered. I know it's a little tricky, special rockers and whatnot. Retainer clearance issues above about 460 lift. Compression jumps up around 10/1. I've read quite a bit about it but no experience with this combination, so I don't want to miss anything. Any words of advice from someone with a little experience? Pitfalls? Things to watch for? Cam advice? (Want a wide, flat torque band) Etc?

Thank You.

a striper

I did a swap in '99 and learned pretty soon that they don't like too much timing at WOT or light throttle driving. As with most iron heads, I deburred the chambers before installing them too.

confab

Any unanticipated problems? Accessory mounting issues? Etc?

RWDsmoke

I ran vortecs for several years on my 86. Worked great. As stated they don't need as much timing. I was even able to run 86 octane with 10 to 1 cr with no knock.

confab

Which head gaskets are you guys using? Gen1 or Vortec?

Does it matter?

a striper

IIRC it was just gen1 gaskets in mine for head gaskets and Vortec intake gaskets. The last set I swapped had been re-worked for higher lift. I swapped in LT4 springs. From what I've heard sometimes they drop in and sometimes they don't, I got lucky. I also drilled/tapped one for a full size temp sender for my C3.

confab

Camshaft recommendations?

a striper

People get more than 400 HP out of these heads but I'd go with bigger heads if I wanted more than that. As a broad brush I'd go under 230 @ .050" with as much lift as the configuration of your set allows safely. I have a modified set of heads with a stock Vortec cam in my '72 as a place holder. It dies by about 5500 but the off idle an up to about 4500 is unlike any 350 I've ever had. I thing the Vortec cam is about 197 @ .050 so it is very small ( I added 1.6 rockers for a bit more lift). For a traffic friendly set up I'd probably stay under 226 degrees @ .050 with about eight more degrees on the exhaust with a manual. For an auto the trans/gears need to come into play for a proper cam choice. It is too easy to end up with a 350 that will not be happy with the stock stall speed. On a street car I would usually go a little smaller with the cam for an auto.


Do you have a cam with known specs already?

confab

No, I don't. I haven't pulled the cam yet, but the lifters are worn.

It may be stock for all I know right now.

Looking for something to optimize this combination. It's an 85, auto. Stock gearing.

Street car.

RWDsmoke

I used the hotcam but I had a roller block. It was a torque monster even with a modified lt4 intake. With 3:07 gears and stock converter and street tires I could launch at 1200 rpms and hit the rev limiter (6200) almost instantly. Didn't take long to break the Dana 36 when it did hook up.