I was just wondering...what kinda numbers would my car make with l98 heads instead of lo5 heads?

Buddy is thinking about buying a set of l98s for his truck and if he doesnt i might for my car...what you think?

 

They're good heads and will respond really well to porting, polishing and bowl-blending. If you can get them cheap, go for it. Anything is better than TBI heads.

If they cost a lot, like $400 or so, then just go buy some 305 heads from the wrecker for $20 and do them up according to my instructions linked at the end of my sig. They'll flow like Vortecs and be able to support well over 400 hp

 

If you replace Lo5 "swirl port heads" with L98 heads wether cast iron or alumium you'll pick up about 20hp on a stock motor.
You'll get more if you port them.

The cast iron l98 heads to look for have a casting # ending in 083
081 heads are the 305 version but wll respond to larger 350 valves and porting just the same.

 

motor wont be stock...ill be changing out the cam at the same time. Then I will have the l98 heads + a cam (not sure yet) + all mods in sig,.

I cant get a set of l98s for 75$

 

Well the amount of power you end up with will be dependant
on the actual combination of parts. But for a low budget/ steet performance motor up to about 400/420 horsepower the TPI (081 or 083 or alumium head) is a good way to start. They will need a good bit of hand porting and bigger valves and a reconditioning. (machine shop visit) Be sure to check and verify the casting#'s and look them over for obvious damage or cracks. Other than that and if you don't mind doing the porting work your self, I say go for it.
A good head for the money.
400 to 420 dyno horsepower (pump gas) is about the realistic potential of these heads in ported condition. A honest 360 horsepower motor will run solid mid to low 13 sec quarter mile times.
You have many of the other nessessary parts to do that now.

 

if i dont do that I may end up just getting a set of world product sportsman II heads. Probably wont port them or anything ill just bolt them on...plus i might throw a lt4 hotcam in there since the world heads can take some nice lift.

 

If you want to buy a powerfull head that you don't have to port,
The SportsmanII's are not the ones.
The quality of the casting is high, no problem there.
The flow of the out of the box SportsmanII is rather modest
relative to the port size and cost.

This head was made for racers to be taken home and ported.
It really comes alive wonce gone over.

You'd be much better off with a set of Pro Action heads
or Vortecs. or Edelbrock Performer RPM.


This is the untouched Sportsman head

050" .100" .150" .200" .250" .300" .400" .500" .600" .650"
Intake 31.0 64.1 92.5 121.7 146.0 172.8 203.6 213.4 221.5 223.1
Exhaust 30.9 64.1 93.3 112.8 123.3 131.4 137.9 141.2 142.8 144.4


This is after a basic pocket port and cleanup

050" .100" .150" .200" .250" .300" .400" .500" .600" .650"
Intake 33.5 64.9 98.2 128.2 152.5 179.3 210.9 240.1 245.8 250.7
Exhaust 29.9 56.8 86.0 111.1 133.0 150.9 176.8 193.0 202.8 206.5

These head are capable of over 300 cfm with professional porting, but by throwing them on out of the box you would be missing out on their powerful potential.

 

This is the flow #'s that someone else on this Board got
by thouroughly porting a set of cast iron L98 heads.
Not to bad at all.





L98 cast heads 083
numbers are:
Lift Intake Exhaust
.1 63.8 41.4
.2 120.6 88.2
.3 178.9 124.1
.4 215.2 154.3
.5 240.1 171.8
.6 241 180