Gibson

so i have a chance to get a running l05 from a friend of mine for cheap. it needs a refresh, but is in good overall shape. seeing as how the l05 has 64cc heads and hte l03 has 58cc heads, would it benefit me to put my l03 heads on the l05 (yeah, ill port em up some and get a good tune). the plan is to run ported l03 heads with an lt1 cam, ls2 valve springs, and 1.6 roller rockers. with a ported stock intake unless i can get a good deal on a used one. any one see any problems with this?

ShiftyCapone

iTrader: (7)

As long as you are not expecting serious power, which I don't think you are, you will be fine. The increase in compression will give you great off idle torque and should supporta solid 250hp+ with a little porting. Tuning will be the key ingredient for this combo

Gibson

250 at the wheels would be awesome, 250 at teh fly wheel would be more than an l98, would it not?

UnderCover89TBI

iTrader: (25)

I think L98's were rated at 230 bhp if I am not mistaken.

Gibson

well for around 350-400 bucks, ill be beating l98s then! freakin sweet!

UnderCover89TBI

iTrader: (25)

haha. Yup possibly. First I wanted to beat 5.0 stangs, then I wanted to beat stock 5.7 iroc's, now I want to beat a 4th gen SS that is close to stock...gotta set a goal!

thomas1976

Dyno Don, has reported 255rwhp with cleaned, 193 casting LO5 heads + LT1 cam + full exhaust.

Gibson

what about cleaned up l03 castings with the higher compression fro the 58 cc chambers? any info on that? or should i just expect an increase of bout 15 hp and call it good?

thomas1976

193 LO5 heads have bigger valves and flow better then the 187 LO3 heads, I doubt that .6 increase in CR will make up for the better flow of the 193's.

Gibson

hmm, since im refreshing the engine anyway, ill just drop som flat tops in it and bump it up that half a point.

UnderCover89TBI

iTrader: (25)

The goal of engines is to move air in and out as good as possible. better flowing heads is better than a little more compression. a 9.5 to 1 doesnt mean a motor can breathe at 6000 rpms any better than compared to a 9.0 motor with bigger better flowing heads.

Gibson

what i was saying is, keep the l05 heads, port em up, and put some flat tops in it instead of the dished slugs that come stock

UnderCover89TBI

iTrader: (25)

I got ya so dont use the L03 heads. Bump up the compression and away you go!

ShiftyCapone

iTrader: (7)

I wouldn't spend money on new pistons to "fit your combo". I would keep the stock slugs and work around that. A little porting goes a long way with either the 193 or 187 heads. Ever point of compression is worth about 4% increase in power. That is a lot more than a few CFM head flow difference.

Gibson

UnderCover89TBI

iTrader: (25)

Ah okay. So in your eyes a lil higher compression is better than a lil more airflow. I can see it either way! but I guess if you dont have good quench your not going to make power. So that makes sense to me

thomas1976

Some later LO5's came with flat top pistons, I would take that LO5 under the lens first.

If the engine is comming apart anyway, there are lot of possibilitys, kinda depend on the budget.

Cheapest is to leave the LO5 as is, 2nd cheapest for around 4hp and 8tq gain should be the 187 with 9.8CR (if they are for free), if chainging pistons there is no point for the 187's.

Edit: I have saved this flow number, from old reserch:

stock 193 int. - exh.
0.100 70.4 - 55.7
0.200 100.2 - 115.6
0.300 145.7 - 125.8
0.400 164.7 - 138.9
0.500 178.9 - 146.8


187 LO3 stock head flow 28 in/h20 pressure drop.
lift_in-----I-------E
.050-----35-----27
.100-----65-----54
.200-----90----113
.300----135----120
.400----158----133
.500----165----140