i already searched and can only find info fo the smaller combustion chamber heads on 305's

I can get a used set of s/r torquers for a fairly good price. Not a steal but its a good price.

My L98 has something wrong internally and the motor is getting torn down come summer, and im putting it back together on a pretty small budget. Bottom end is getting left alone just a stock rebuild. I'm going to be getting a cam to match whatever heads im using. And for now my intake will be a stock ported intake and runners, which will later be swapped for something better that wont choke out my motor.

The stock l98 heads on my car were ported by a previous owner, i would assume just a valve job and such.

The torquers have been milled down to 72cc combustion chambers from 76. With as large of cam as is reasonable for these heads how much power will i be able to make with them? and is it worth getting as opposed to using my ported stock heads?

 

I ran mid 13's with those heads Edelbrock headers & Lunati 218 cam on an otherwise stock L98. The springs that come on them are worth poo though.

 

mid 13's eh?
I think i can probably get a high 13 out of my ported l98 heads, a cam and intake. The torquer would cost me 600 canadian with aftermarket springs and rockers with only 3000km on them.

Dont think its worth 600 bucks tho

 

I would pass on the heads spend $500 on NOS, save a $100 and make a 100 more hp...

 

Thats probably because they are S/R heads. That stands for service replacement. The plus size is they have tons of meat for porting. Another board I frequent plans on flowing a set of these after being thoroughly ported. Should be interesting on what flow numbers they get. Ive seen the topline torker heads which probably flow better for much less than what you posted too. The L98 heads thoroughly ported can flow just as well.

 

I found flow numbers to ported torquer heads here.

http://www.caspeed.com/488hp383.html

Thoroughly ported S/R torquer heads 180 cc intake runner 165 cc exhaust
Int
100 81.2
200 151.3
300 213.7
400 252.8
500 257.7
600 265.8
700 269.8

Exh
100 65.8
200 122.7
300 148.8
400 161.8
500 172.1
600 176.6
700 177.0

The 383 engine made 485#/Ft of torque at 4200RPM and 488HP at 5900RPM

 

thats really interesting

any idea on what your average shop would charge for the port work they had done

1- Pocket porting/bowl blending
2- Porting the exhaust and intake runners
3- Gasket match the intake and exhaust ports
4- Trim back the intake valve guide casting

 

It wont be cheap. If you got guts you can port them yourself. Lots of good info on this site on porting heads. I believe vader has some templates too. You could get a set of these and port them and probably get some decent flow numbers.

http://cgi.ebay.com/ebaymotors/NEW-S...27340682QQrdZ1

 

S/R = stock replacement
Sportsmans are the next upgrade.

 

Look here:
http://www.worldcastings.com/docs/05_cat_pg16.pdf

 

Keep your ported L98's and save for some real heads if you want more power. Instead of spending $ on heads i would invest in a new intake. Right now the TPI intake is the restriction not your heads.

 

I'd opt for exhaust if that hasn't been done.

 

I already have some slp headers from *** knows how long ago, theyre weird, its 4 into 2, then the piece that came off the two was custom made and garbage. Had a new custom piece made and those headers go into a 3" mandrel bent y-pipe.

The motor has to be rebuilt because something internal is wrong, i get a vibration that gets worse and worse steadily as u climb rpm.

I'm putting in a new cam, and was hoping i could get a set of heads so i didnt have to replace the cam again later. Was hoping for something i could run low 13's with. My goal for this car, or at least while still using the current block, is to see a 12.99.

For now ill be using my tpi intake that im going to port myself, and will be replaced im thinking with a stealth ram probably part way through the summer.

Problem being is i only have about 2500 dollars canadian to have the motor torn down and rebuilt. Am assuming the crank and rods are re-useable.

Any ideas are welcome. Thanks all you guys for help on deciding if i should get those heads. Saved me 600 bucks

 

Your stock castings when fully ported have as much flow potential as the professionally ported S/R's. If not more.
Your heads have a better combustion chamber shape.
(more centerally located spark plug)

Your heads have probabily had just the most basic porting (pocket porting) if at all. You've barely scratched the surface.
You can end up at the same flow point using your present castings. And maintain the compression ratio.
Fully port your heads, *yourself*. Have them rebuilt with new 2.02x 1.60" valves. You probabily won;t achieve the same flow numbers as the pro ported S/R's but you don;t need to. But you will get close enough. You'll end up with a smaller/ higher velocity 170cc TPI friendly port as well.
Anything around 225 to 230cfm will get the job done on a TPI motor. You can easily exceed this at home with a true effort.
When you get it apart post some picks of your heads showing the ports and bowls.
They will need a full porting, not just a pocket port.
You'll be carving about 10cc's of metal out of each port.
There is lots that can be done to improve them.

The S/R's aren't going to add much value to your project.
They would need complete porting also and the cr will be lower. If you are using a larger duration than stock cam you probabily want to raise the cr a little more towards a true 10:1. ( block decking, head flat milling)
You definatly do not want lower compression.
Spend the money on rebuilding your heads and the tools to port them.

 

sounds good to me, i already have a compressor so tools and bits is all i need to do the porting.

I've never ported anything before but ill find a set of junk heads to try on first, then go at my own. Ill post pics when i take it apart.

whats the most lift l98 heads can take? probably be wasting money going with big roller rockers?

 

Don't worry what is the lift limit. Measure it for yourself and have the machining done that is needed.
Roller rockers are not a waste but do add to the budget.
Spend the $$$ where it will do the most good first, not what looks or seems sexy. Heads, cam exhaust bla bla bla rockers.....

Pick the cam and then get the rockers that suite it and your overall budget best.
What is the rear gear ratio, tire diameter and what is the torque converter stall speed that you have?
if youre chassis is basicly stock with a stock converter you want a modest duration cam with fast action and high lift
1.6:1 rockers help here.

Something around 212-226 in/ex @.050 is about as big as I'd go unless you have more gear and a high stall.
TPI motors are "torque motors" not high rev-ers. Its easy to over cam them. But the ported heads will like high valve lift. Lingenfelter used a 219-219 .560" lift cam with great success in TPI motors. At .560" lift a roller rocker is called for. ( 1.6:1)

Narrow body Crane Gold, Scorpion or Comp Pro Magnum work well. Crane stamped steel roller tip will get the job done on a budget. they are much better than a stock GM rocker.

 

i dont plan on leaving the tpi intake on it for long if at all. Probably when it goes all back together its going to have a hevily ported tpi on it, but within a month or two thatll be replaced with something that can support higher rpm so thats not much of an issue.

With higher rpm id be more worried about strain on the stock bottom end.

I guess ill probably get my heads flow benched, if i can afford it no idea what thatd cost me. Once i know flow numbers on my heads, i can pick the perfect cam for the motor.

As far as transmission i swapped in a tko-600 5 speed not realizing my drivetrain vibrations were coming from my engine. Just had that in near the end of last summer. I still have 3.73's in my rear end but im going to have to live with those until i can afford new gears cause no point in wasting money on gear install when its just a matter of time until i frag my 7.5" 10 bolt.