Hi guys, I have an '86 IROC and I'm concerned about a couple details with my planned Vortec head swap. I'll be getting the Scoggin Dickey performance vortecs in about 3 weeks. I would have already had them but an unplanned rear end failure forced me to extend it a bit. I bought the car used with a new engine. The engine is a Pep Boys 350 longblock with a high volume oil pump and Moroso 7 qt pan, Comp 280 magnum cam, Performer RPM intake and a 750 cfm performer carb. Th heads are as provided on the motor from Pep boys The drivetrain consists of a brand new Moser 12 bolt w/ 3.42 gears, a TH 350 w/shift kit and cooler and a Daco 2600 stall converter. My first question is about the cam, I was planning to get the Extreme energy 268 from Comp and running the 1.6 roller tips all around. However, this cam has the same exhaust lobe specs as the 280 magnum (which is a single pattern cam) so I was thinking about keeping the 280 cam and using 1.5 rockers on the intake and 1.6 on the exhaust. Sound like a good idea? Or would I get the best power from switching the cam? My other question is which head gasket should I use with the vortec heads on the 350? I believe I'll need a somewhat thicker head gasket for this, anyone have a good Fel Pro part number? Thanks for any input, much appreciated. AD

dont use the 1.6 rockers with the vortecs, the locks will bind on the valve guides at high RPM. Ive heard and read that the vortecs like a split grind more than a single pattern like your 280 and the 268 would definately have better road manners. Id say stick with the stock rockers, get 981 springs and the 268 cam. You will be very happy with this combo.

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91 RS W/carbed 350, Vortec heads, performer rpm, Comp cams Xtreme energy 224/230 duration and .477/.480 lift. BFG Drag radials. 3.42 posi,Corvette servoed 700r4, 3000 stallconverter. Edelbrock TES, 3inch cat, flowmaster with single 2.5 inch exit.
Best time yet to come
12's?? :crossthumbs:

This is a Pic of my car in race trim www.tbns.net/billyjay/camero.jpg

Yes I know how to spell camaro- so dont ask. I didnt make the link

I forgot to add my exhuast system above, I have Hooker 1-5/8" shorties going to a flowmaster y pipe, single 3" to a Flowmaster 2 chamber dual outlet.

I'll be getting the modified vortecs from Scoggin Dickey, here's a link to the heads;

Modified Vortec Heads

Hope I did that right :~)

Anyway, I shouldn't have any interference problems with these heads.

The vortecs really like a dual pattern cam, because of their not-so-great exhaust flow numbers compared to the pretty good intake flow numbers. I'm not sure if the different rocker ratios on each would be enough to get the full power out of them. A 268 isn't much money, I'd just switch to that and run 1.6s on both valves... And according to the specs on the HP Vortecs you shouldn't have a problem.

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

And if you run that cam, have screw in studs put in over the pressed in studs.

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,TRW Forged pistons,10.7:1 compression,HPC Coated RPM intake, Speed Demon 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, Comp Cam 1.6 roller rockers, Comp Xtreme 284 cam,240/246@.050 with .540 lift,Crane pushrods,ATI damper,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with B&M 3000 stall, Powertrax NoSlip Locker, 4.11 gears.

Thanks Ray87z. That was what I was waiting for. I'll go with the 268 and 1.6 rockers.

Just for reference, the hp vortecs are machined, and have springs, for a max lift of .55". They also have been drilled and tapped for screw in studs. They should be very durable and provide many miles of smiles.

Now for the head gaskets; the heads have never been removed so I have no idea about the deck height. I've located a Felpro gasket at summit with a .041 compressed thickness that looks good. Would that put me around 9.5 compression?

Thanks again!

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91 RS/3.1 - Stock except stereo system, daily driver.

86 IROC - Pep Boys 350 longblock, Performer 750 carb, Performer RPM intake, Comp Cams 280 magnum, Hooker 1 5/8" shorties, Flowmaster Y pipe, 3" pipe to Flowmaster 2 chamber Dual outlet, TH 350 performance rebuild w/shift kit, Daco 2600 Stall, 3.42 Gear Moser 12 bolt w/Eaton posi.

I say go with the XE268 cam....my cam of choice also but go with the comp magnum 1.52 roller rockers! The 1.6's will cause you problems!! Also, the comp magnum rockers will fit under a stock valve cover unlike most rockers!!

As far as head gaskets...get the .039 gasket!! The thinner the gasket, the more compression! Depending on your pistons, with a .039 thick gasket you'll be well over 10:1 compression!! Unless of course you have dish pistons then you're lookin' at about 9:1 if you're lucky!!

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1986 Trans AM
305 TPI
200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Soon to upgrade to a 383 converted from TPI to Carb, Edelbrock 600CFM Carb, Edelbrock Performer RPM Intake, Hedman Shorty Headers, AFR 195's (if I can afford them), XE268 Cam, Moroso HEI ignition kit with external MSD Blaster II Coil and an MSD 6-AL Box!!
Current project: Keeping my 305 running until I get my income tax returns!

Does anyone agree with 86TpiTransAm? Or should I go with .041"? I would rather err with slightly less compression than with too much.

Thanks!

I would use the .041 Fel-Pro gaskets......IMHO

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,TRW Forged pistons,10.7:1 compression,HPC Coated RPM intake, Speed Demon 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, Comp Cam 1.6 roller rockers, Comp Xtreme 284 cam,240/246@.050 with .540 lift,Crane pushrods,ATI damper,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with B&M 3000 stall, Powertrax NoSlip Locker, 4.11 gears.