What to do with the heads?
Registered User
Joined: May 2004
Posts: 714
From: Ewing, NJ
Re: What to do with the heads?
Originally Posted by WS Sick
We pocket ported a set of 86 305 TPI heads,gasket matched, added 1.94 intake valves with a 3 angle valvejob, backcut the valves, and removed all casting flash throughout the port. We stuck these heads on a stock 90 350 TBI shortblock stuck the 86 TPI equipment back on and put it in an 86 T/A. The car ran consistant low 14s (no cats, homemade cold air, cat-back, 2500 stall, 3.42 rear) at 97 to 99 mph. We later added some ported 193s with basicly the same work, removed swirl vanes. and gained a few hundreds of a sec. (well within correction factor)
- Justin
Thread Starter
Banned
Joined: Apr 2004
Posts: 1,610
From: Holland, NY
Re: What to do with the heads?
Wow.. that is really good timing for only having that head work done on your stock head! Hooking is gonna be a problem for me as well.. 350 lb's.. one-wheel peel.. 
Registered User
Joined: Dec 2003
Posts: 2,724
From: Oklahoma where trees are made of wood.
Re: What to do with the heads?
Originally Posted by Tru2Chevy
That car wasn't hooking very well, was it? That mph is plenty to get into the 13's.
- Justin
- Justin
But what can you expect from GSCs?
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Joined: Oct 2004
Posts: 100
From: Littleton, CO
Re: What to do with the heads?
Originally Posted by 85_305
I will call around local junkyards and find out if they have any LO3 or LG4 heads. .
Everything said should only be assumed to apply to either your current '85 heads, or '87-up 081 casting 305 heads.
As for the aluminum L98 heads: 58cc chambers are too big for a 305. The factory went from 64cc iron to 58cc aluminum on a 350 to make up for the heat loss (read: power loss) through the aluminum material. On a 305, they should be milled down to 52cc. Similarly, Vortecs should be shaved down to 58cc.
Registered User
Joined: May 2004
Posts: 714
From: Ewing, NJ
Re: What to do with the heads?
Originally Posted by 85_305
Wow.. that is really good timing for only having that head work done on your stock head!
- Justin
Thread Starter
Banned
Joined: Apr 2004
Posts: 1,610
From: Holland, NY
Re: What to do with the heads?
What is "swirl port" technology? I am assuming that my heads do not have it? According to Justin, (tru2chevy) the Aluminum L98 heads are PERFECT for aftermarket heads for my Z.
"Don't forget...they also went from a 305 to a 350 to get those times...."
Sheeit.. I forgot about that part
"Don't forget...they also went from a 305 to a 350 to get those times...."
Sheeit.. I forgot about that part
Registered User
Joined: Dec 1998
Posts: 2,161
From: Haslett, Michigan
Re: What to do with the heads?
Originally Posted by 85_305
"Don't forget...they also went from a 305 to a 350 to get those times...."
Sheeit.. I forgot about that part
As for swirl port technology, the L03 got some heads that had a vane cast into the valve pocket which was supposed to induce swirl into the charge in order to get it to spin out from under the valve face and induce turbulence into the combustion chamber on the compression stroke. Think of it as the OEM equivilant of the "Tornado". Whereas it might in theory have helped low-end torque, in fact it reduced air flow volume and velocity, rendering the L03 heads LESS than optimal for a performance standpoint.
Registered User
Joined: Dec 1998
Posts: 2,161
From: Haslett, Michigan
Re: What to do with the heads?
Originally Posted by 85_305
How much hp and #'s did the L03 put out? DId it in all reality help w/ torque?
http://customclassictrucks.com/techa...0405cct_head/#
Registered User
Joined: Dec 2003
Posts: 2,724
From: Oklahoma where trees are made of wood.
Re: What to do with the heads?
Looking at some LO3s you'll shove sell them for scrap or use them for credit at the machineshop (if they'll take em). The ports are tiny and the breathing capability of them is low. You also have what they call "lightweight" castings in the LO3s. I would pass on them either way.