I want to build a 350 that will run on regular unleaded fuel for street car 91 Camaro. Question is should I build a L98 350 or the Vortec 350. It will be carb motor with HEI. I know about getting a intake & carb, but which would get me the most power for the buck? I see we can get a L31 new from Jeggs pretty cheap. I know on either heads if you run a high lift cam the heads will need to modified to accept upgraded valve springs. On the headers do the Hooker 2055 come with non-air?
I did a lot of reading so far and have ideas but others have been through this and wanting to get some input. Cam suggestion. Idle quality not a problem with a manual trans. Yes T5 but found a T56 complete set up already.
JP

Regular unleaded? as in 87 oct? Keep compression around stock low 9's to 1 with either head and it will work just fine.

Just go easy on spark advance.

Vortec head will make another 20-30 hp over an L98 head on the right combination of parts. If you can get those heads, I'd run those over L98's.

Now the aluminum L98's are nice in that they give you 50lb weight savings but dont really flow any better than the Iron L98's. But they do have good potential to make power after porting. Aluminum is easier to port.

Street car builds with a carb, typically looking at a dual plane intake, like a edelbrock performer rpm or similar. There are a bunch of comparable intakes out there.

Cams will vary. If this is a roller block from your 91 or you get a late model L31 with roller cam, run a roller cam. Cheap budget cam that works and makes decent power is the LT4 hotcam. Can find these for 100-150 bucks used on various forums...look for LT1 car forums as its a popular cam for those guys.

Something in the 218-224 deg range is streetable and can make good power with vortecs. Still run on 87 oct just fine although tuned for 93 will make a few more ponies with more aggressive spark advance.

Lots of cams in that range to choose from, just need the heads modded to handle the lift. It is possible to get abit over .500" from the heads without much more than a spring/retainer swap and modification. Beehive kit supposively will give you .520" but you'd need to verify that. Some guys claim .550 on some dual spring upgrades with cut down retainers.

Most roller cams in the 218-224 deg range on the intake have between .490-.550 lift. You'd want to stick to something in that range for sure, .500-.520 is a good range.

Dont think the 2055's come without air...but you can shave those off and weld the holes shut...but your paying extra for those air tubes. Hooker makes the 2460's but no y pipe i believe.

I'd go with the Patriot performance Vortec head @ $735.00 FOR THE PAIR, they come with 2.02 valves, springs to support a .550 lift cam, and stiff enough to handle most hyd. rollers, so flat tappets won't be an issue, Edelbrock Performer RPM air gap & 750 Edelbrock vac secondary carb, keep the timing at or below 34* total and you'll have a great performer on top of nearly any flat top 327-350-400 SBC! now as for cam selection, I'd look at grinds with .525 lift 225-230 duration @ .050 and 110 lobe sep. with your manual tranny set up shifting a 6000 rpm max!

Will the Vortec heads fit any 350 block or must it be a vortec 350 block?

vortec heads will bolt to any gen 1 SBC.

id go with the vortec heads
ive HEARD bad things about patriot heads i was thinking about getting some but after reading what pll said think im gonna go with the rhs vortec heads

I have had no problems with my patriot heads. Most of the bad things I have read online are 5+ years old and all centered around the same set of aluminum heads.

I am thinking a new L31 Vortec from Jeggs, LT4 cam and will get a Vortec intake and plan on 650 spreadbore with mechanical secondaries and new HEI, and Hooker 2055 headers. For a street car that will be fine. Thanks for the input. The Patriot heads are very interesting and maybe just a find good core and put those on the top half. Really appreciate the input. This car was bought as just a beater but it was solid and rust free it got new paint, IROC hood, rims and grill, new posi and exhaust. Yep sub frame connectors will be first and then the motor swap...

Will the flywheel from my 91 fit the Vortec 350 and does it have the 1 piece rear mail oil seal?

the 91 will be a 1piece rear main and be 153 teeth. the L31 long block on jegs is an exact duplicate of the L31 HD truck engine, which is a 1 piece rear main as well. stock L31 put down a lil over 200hp and 230 tq in the HDs. id suggest swapping the cam thats in there before installing it. the lt4 hotcam has too much lift for the stock vortec heads with the stock springs. you might be able to get away with a set of beehive springs and the lt4 hotcam without having to machine the heads.