zrs

hello,
Need help in building a motor. I have an L98 shortblock and looking to put vortec heads on the set up. Need help in the following:
1. What part # vortec heads to put on
2. Recommended cam to use.
3. Can I swap my flyweel on a 1988 305 tbi to the 350?
4. Need to get self aligning rocker, go with 1.5 or 1.6?

Rice Killer87

the cam u choose would depend on a bunch on things...like passing emissions,how r u gonna drive the car,etc etc. i have a Comp Cams XE-270-HR cam and has .495/.502 lift. doesnt sound like a race car but does have some lope to it. i think the next car up is the XE-274-HR and i think its the biggest u would wanna go w/ if u have power brakes (which im sure u do). not sure what the lift is on that tho.

i have those heads on my car and the part # doesnt matter as long as they are Vortec heads. dont forget u have to upgrade the springs and everything also.

yes,the flywheel will work.

in order to use the 1.6 rockers,ull have to have really good springs b/c that 1.6 ratio is gonna give u more lift and if the springs cant take it then u cant use those rockers. if i was u,i would choose the cam,then choose the 1.6's u want,and buy vavle springs accordingly...just my thoughts.

AutoRoc

This link has modified Vortec heads for use with more aggressive/bigger camshafts for very reasonable prices. I'd do the Roller cammed versions for what you're doing. http://www.sdpc2000.com/cart.asp?act...art&catid=2172

For a cam I like this one: http://www.sdpc2000.com/cart.asp?act...686&pid=123556

And this one..http://www.sdpc2000.com/cart.asp?act...1989&pid=29782

I'd do 1.5 rocker arms. These cams have enough lift and very aggressive lobes for Hyd. Roller designs and an unmodified Vortec probably doesn't want to see much more than .550" of lift just for airflow reasons. Everything about that head is small and efficient, when you start getting into big sloppy cams, it's just not a good combination.

Figure out what your compression ratio will be once all said and done. Not sure if you'll be getting the new heads milled or what kind of head gasket will be used. Calling a Comp Cams, Lunati, or Crower's tech line would be helpful in figuring out what cam might be best for the combination, Goodluck!

zrs

Thanks for the input, as far as vortec heads go, I will use the 062 casting since I was told 906 did not flow as well as the 062 and the 059 were for 305's. The springs will be replaced to match the cam.
I was told that the compression on the engine would be 8.5:1 using 58cc heads. Still would like to bump up the compression and still be able to use pump gas.

Rice Killer87

yea,9:1 or 9.5:1 or so is a good street compression i think. u could prob. get that w/ getting a thinner head gasket. im not sure what 1 u would need to do that,but im sure some1else can answer the question for u.

Vortec heads for 305's ?? r u sure? i didnt think they made them for 305's b/c there isnt a 305 in a vehicle thats produced is there?

Pro

trucks

Ray86IROC

What is your planned use of the car/power goals you're trying to hit? Those cams linked to above are quite large for a regularly street driven 350 IMO. I'd just go with the tried and true LT4 hotcam kit with the included 1.6 rockers, and get the heads machined to handle the lift and accept the LT4 springs included in the hotcam kit. Boom, easy 400+ hp with a decent tune and good intake and exhaust setup, but you didn't mention what you're planning to run intake wise BTW...

I'm fairly happy with my carbed Vortec 350 setup. Just running unmodified Vortecs with the CompCams XE262 cam (non-roller, 218/224 @.050, lift of .462/.469) with a Performer RPM intake, headers, etc. I would like in the future to get the heads modded to accept some more lift and step up the cam just a bit or at least 1.6 rockers...

As long as you get 906s/062s you will be fine, the thing about the 906s not flowing as well is incorrect and is from a mistaken statement in CarCraft or maybe it was Chevy Hi-Perf mag. They corrected the statement later...

zrs

My goal is to at least reach 300+ rwhp. Thanks for the info on the 906’s but I have the 062’s in hand. As far as intake wise, like to keep the TBI set up but am told they can not feed a motor past 300HP. Even with a Holley 670 tbi or 454 tbi set up. Would go with carb but since being in California, smog laws would not allow it. TPI or even after market ones would be great but cost $$$ and know little about them. What would you guys suggest?
How about using a zz4 cam?