COTY'S IROC-Z

what head is the best head .. 350 vortec head or a l98 head???

Fast355

iTrader: (2)

The Vortec is a much better head.

92droptopws6

iTrader: (10)

even fully ported the cast iron L98 head cannot flow the way the vortecs can. stock L98s are great boat anchors

Doom86

This is false.

Ozz1967

iTrader: (4)

LOL Not that I totally disagree, but which part? Apples to apples, stock the Vortec is better than the stock L98. Ported, the L98 can approach and even surpass the stock Vortec's but if you do any work to the Vortec's you're better off with the Vortec's. So, if your looking to drop that kind of money, you might as well pick up a set of AFR's, may even be cheaper by that time.

Rob's 92 gta

COTY'S IROC-Z

thank!! i got 275 dollar in the vortec heads an they have been cut 15 thousands..

Orr89RocZ

iTrader: (20)

False. With full port work and 2.02 valves, L98 Iron heads have been ported to 270 cfm. L98 113 aluminums however seem to only get to 250-260cfm. I dont know of any small port vortecs getting 270cfm but it may be possible. Atilla may know since he ports them.

Out the box the vortec head is better due to more flow and chamber design. When ported, its all in the combination. Both heads would need modified/machined to accept higher lift cams but vortecs dont really like much over .500 lift anyway so not much work needs done to accept that kind of valve lift. 113 L98's are 40-50lbs lighter so thats extra ET right there

I dont know of many big hp vortec combinations out there but have seen some impressive 113 head combinations in the vettes. They are similar to a LT1 head and a stage 1-2 LT1 head setup flowing 260cfm will make 380-400whp.

If doing max effort TPI, the vortec bases dont flow as well as regular TPI aftermarket bases so theres more power to be made with TPI. I'd venture to say that vortec HSR may not flow as well as the regular HSR due to port shape/design but cant say for sure. Dont know the dimensions of the vortec HSR runners/ports. For carb setups I'm not sure either if a vortec version of an intake has smaller runners

Doom86

Read Orr89RocZ's reply it's exactly what I was getting at. Iron L98's are not bad heads in stock form; not great but there are few stock castings of our era as good as them. In ported form they are much better then stock Vortec's, they don't "approach" their flow they surpass it with little effort. With max effort, as Orr89RocZ pointed out, they are quiet awesome.

The highest flowing Vortec head I've "heard of" is 270cfm, and the same is true for the Iron L98's.

Orr89RocZ

iTrader: (20)

Putting that much time and effort into Iron L98's just doesnt make much sense when you can buy aftermarket for about the same if not a bit more money that will out perform the L98s. They arent a bad iron head if you want to use them and dont mind doing the work. Even with stock sized valves, they can flow very well to make plenty of power.

Damon

Since you already have Vortecs on the motor, stick with them. Certainly I wouldn't swap them out for a set of L98s (Vette or F-body) which would require a different intake than you have now, adding even further to the cost. If you want to step up significantly performance-wise then you're looking at a set of aftermarket heads (like maybe a set of AFR Vortec-style heads), etc., etc.

But for a small of bucks it's very difficult to beat factory Vortecs (which you already have).

92camarorv6

sorry dont know how old this is but the vett l98 heads are batter for a tpi that fully ported then the vertec? some of the wording thow me off

Ozz1967

iTrader: (4)

A set of ported and polished L98 heads are better than Stock Vortec heads.

A set of ported and polished Vortec heads are better than a set of ported and polished L98 heads.

So, if you have the vortec's already, keep them and use them. If you have a set of L98 heads, port and polish them...and keep them.


But those are just suggestions. In the end, it's up to you.

InfernalVortex

iTrader: (4)

Id avoid porting the intake side of Vortecs. They're really very good and it's about more htan just pure flow numbers with them. The port shape itself helps them function so well. Also the vortec combustion chamber design is miles ahead of the L98 chamber design.

Am I saying it's worth it to jump from L98s to Vortecs? Nah, I've seen tons of 113 headed 350s pull some very impressive numbers. But if you've got vortecs already, they're very good, I'd just leave them alone and run them. They're great factory heads. I'd NEVER suggest anyone switch from vortecs to L98 heads though, the only exception would be if weight is a huge concern and you're going to aluminum heads to help the car's weight distribution for autocross/road course work.

Kevman

I went with the L98's..
This may sound goofy, but it made sense to me while building my engine.
In my area, the dirt track guys have bought up 90% of the good Vortec heads.
What's left has already been raced, cracked, or not vortec 350.
Case in point.. I was hosed on a set of 305 vortec, by an engine builder, it stings, but you get over it.

Comparing the two side by side price range, as to what mine required to work with my cam/rockers/engine, the L98 made more sense.
I walked out paying around $700 with redoing the heads with new springs, machining the gasket surface, back cutting the valves, new seals, bead blasting, blah blah blah. The $700 included purchasing them.

The Vortec, because you're an american fellow, is probably the best deal. You can go to your local GM Goodwrench dealer, and buy replacement heads at about what I paid to re-do mine. Here, one head is over $800.

The L98 isn't as horrible as everyone will lead you to believe, with work, it's actually quite decent, and it's the same head GM uses on there 290hp crate engine. Do some research online, you can pick up a set of 083 L98 heads for around $50-$100, you don't have to be as extensive as I was with the back cutting, and porting, but it does make a difference.

dabird07

iTrader: (10)

from this book i have the l98 heads are used both on a 350 and 305 tpi
same specs correct me if im wrong

InfernalVortex

iTrader: (4)

5.7 Liter L98s got 083 heads.
5.0 Liter LB9s got 081 heads.

The 5.7 heads have 64cc chambers.
The 5.0 heads ahve 58cc chambers.

They are most definitely separate heads.

The 081 heads aren't bad, I think they're just 416's with a centerbolt valve cover, but I havent been able to verify that in any way, and both 081's and 416's can make serious power if set up properly. I have also heard that 083 heads have the same runners as the 081 heads. The difference is the larger chamber and I think larger valves probably.

They are not the same head, but they are similar, and they are decent.