Hey guys I was just wondering are l98 iron heads any good I mean they have the stuff to be decent it’s got 64cc chamber 1.94,1.50 and 165cc runners has anyone ported and polished them or anything like that can you actually make power with them?

 

No of course no one has ever tried porting them. Why would anybody do THAT? You're the first person that's EVER thought of that.

Seriously, ... no, really, it's been done. Hard to believe I know, but it's true.

They're roughly equivalent to the more common of the old double-hump heads like 186 in terms of flow potential and all that. Not the same in every detail of course, but roughly equivalent. A decent platform to start out with for such things, as such things go. Better than, say, 624, 882, etc.

Problem is of course, in 2021 as opposed to 1976, you can just go to the store and buy new castings that will run circles around them, often for less than it costs to work up a set of old stockers to an equivalent state. In 1976 there wasn't a choice; in 2021 there is. Apart from porting (not sure why everybody always adds "and polishing" to that) that you can theoretically do yourself for low $$$ and take your chances on whether you actually KNOW WHAT YOU'RE DOING or not, further performance-oriented upgrades like better valves, cutting the guides down for Teflon seals, opening up the spring pockets for bigger springs, machining for screw-in studs & guide plates, opening up the push rod holes, repairing all the bolt holes, and on and on and on and on, all cost MONEY. While at one time this was what we all did because we HAD TO, in 2021, it's not generally worth it. By the time you do all that you have 80% OR MORE of aftermarket money tied up in them, and you still only have a set of old stockers. And of course, aftermarket ones generally ALREADY HAVE all that stuff, out of the box.

As far as "actually make power", I guess that depends on what you mean. If you mean, "compete with aftermarket", then NO. If you mean "improve an otherwise stock motor somewhat", then yes.

 

Yea, 083 heads are decent. My Dad spent about a day doing some light porting and polishing on mine. Don't know exactly how much it helped but he claims a lil cleanup on these heads can really help especially on the exh side. Car does run pretty strong but again I don't know how much it helped. A set of stock Vortecs are probably better than a set of ported L98s but I used the L98s because they were compatible with my intake and made for a simple swap, wasn't trying to build a race car. Like Sofa said if you want GOOD heads.. money would be well spent on aftermarket heads like AFRs or Trick Flows to name a few.

 

Ya I was just wondering I was gonna go for aftermarket anyway but the prices of heads now are crazy for me to buy a set of Afr heads it will cost me the price of my car (1,000$) plus the price of my new 350 (700$) it’s kinda crazy

 

Ive seen carbed swapped L98s run very good times with minor upgrades like cam + springs and good exhaust. These heads are probably plenty good enough for what you have in mind.

 

If all you're looking for is a cheeeeeeeep upgrade, then yes, porting a pair of 083s is a reasonable way to go. Leave "polishing" out of it.

About 80% of the gains on a set of stock heads is usually found within about ¼" of the valve, in the throat; along with trimming the guides to a "teardrop" or "airfoil" kind of shape. It consists of, removing all the steps and ridges and weird angles that resulted from the factory just jamming their cutter down into there; and GENTLY rounding over the short-side radius WITHOUT lowering the floor (remove as little metal as possible). A GOOD HIGH QUALITY multi-angle valve job, on both the castings and the valves, is about another 15% of the total available benefit. Raising the roof of the exhaust port as it exits toward the headers can help. Removing any sharp edges in the chambers, particularly where the chamber meets the deck after machining the deck flat, will help keep it from pinging as much. Needless to say, somebody with a flow bench and a whole pile of cores, or with templates, or LOTS of experience with your particular casting #, can do MUCH better than a shadetree like me. It's plenty possible to completely ruin a set of heads by overly aggressive use of the grinder.

Don't bother with "polishing" whatever that is, or "gasket matching", or any of the rest of that. It accomplishes approximately NOTHING, and is merely eye candy to fool the inexperienced into paying more for the work without actually doing anything that has to be proven as "worthwhile".

Valve springs, goes without saying. No aftermarket cam can work with stock valve springs. Even a motor with a stock cam can run CONSIDERABLY better just from replacing the springs. I'd recommend a set of LS6 springs and the Comp 787 "adapter" retainers and their matched keepers, set to 1.75" installed height.

Not to rain on your parade, but I doubt that anything you can do to a set of heads, is going to make much difference on a $700 "new" motor. I don't know how it's even possible to sell one that cheep. Last motor I built had more than that in just the machine work, before I even bought any of the parts like pistons or bearings. I can only assume that every possible corner in the whole process was cut. Good luck with it though, I have a feeling you're going to need some of that.

 

Valve spring replacement:

https://ls1tech.com/forums/generatio...d-all-day.html

 

Yearsss ago a guy on this board ported a set, in several stages

eventually, fully done with larger valves, they flowed over 270 cfm. Extremely impressive, thats enough for well over 500 hp in the right hands

but very few are willing to spend that time porting iron lol takes a long time lol

i’d rather hold out for a set of aluminum 113 L98 castings so atleast you save 50 lbs off the car, and slight compression increase, despite flowing about the same

 

Ya thank you for the info but by polishing I just meant to clean it up after the porting to give it a smooth it out as much as I can but ya the engine I mean it’s basically new it is a “new” engine because it is from an iroc and has extremely low miles under 100 but sat for 30 years so it’s technically a new engine but obviously old so it’s kinda hard to explain I just have the l98 heads an a set of 416 casting heads from a 305ho with the 1.84,1.50 valves and 58cc chamber those are pretty good but u heard they don’t have good top end an can’t take much of a cam and I doubt it would flow enough for my monster carb I’m still planning on getting dart heads or Afr or something but I was just seeing out my options any of you guys have experience with the 305ho heads I’ve heard great things and bad things so I don’t really know also I have yet to pull the heads on my 350 so I don’t know if I got dish or flat tops either

 

Also though I know I can’t do it with the stick heads but my goal is an 11 second car even if it’s 11.99 I’m gonna for the engine have the dart heads most likely 525 lift roller cam, edelbrock performer rpm, flat top pistons, headers, accel distributor, and a holley 800 mechanical secondary to top it off and I will have 28 inch Mickey et streets as well as 4:11 posi and an auto trans

 

Look on the speedtalk forum.
Member Carnut1
all about porting the 083 l98 cast head
Different progressive valve sizes with porting and chamber mods too..
the TPI Project thread..
He has also done extensive work on the 081 305 tpi head with impressive results.
Yes you can make very good power with both these tpi heads with agressive porting ,chamber mods and various valve sizes..

 

thank you I will check it out

 

Well that was a bust I go to speed talk and it says that my email is in use even though I never even heard of the forum makes sense

 

Unless you are bracket racing, or seriously drag racing I'd skip targeting an ET and just build as much power as reasonable for your budget while taking into account required driveline upgrades to keep it reliable. You'll be happier on the street that way.

 

it’s going to be a mostly strip car it’s gonna be more of a street legal drag car than a street car that can race

 

Smooth intake ports dont make power contrary to some belief lol

mirror polish chamber isnt a bad idea tho

 

Start by weighting your car with driver.
With this you can calc how much horsepower
you will need for xx performance.
And or how much weight will need to come off the car
to get the performance with the available power..

 

Right now it shouldn’t be too heavy it’s just stock I don’t have a passenger seat or console and I have a fiberglass hood so it should be a decently light car

 

Go weight the car.. Stop dreaming.

 

If you want to get a real high 11 second ET with a hot 350 sbc using FULLY HAND PORTED 2.02-1.60 VALVE
correctly reworked 083 L98 heads on a reasonable budget Get the car true scaled weight down to 3000 lbs or less (3200 lbs MAX with driver.
Plan on P255-60R-15 27" tall ET street SS drag tires, 4.56 gears ana 4000-4500 stall 9"-10" race converter
(TH350) Use a solid lifter cam or solid street roller cam.. 10.5:1 cr 750+ cfm carb. Vic Jr or holley 300-25 strip dominator intake.
Ya it will buzz thru the traps at 7000 rpm.
But it will get you there in just under 12 seconds.
The L98 heads need full porting to get real 250 cfm flow + not half *** bowl porting..
You need to step on it to get 11's.
Race ready true car weight 3000 lbs.
If it does not make the car GO, STOP, or Steer remove it or replace with a lighter weight replacement..

You are at about 3550 to 3650 now with driver.
Get the car weight down to 3200 w driver max for this.

Member mw66nova has a good thread about lightening your car up to 3000# Race ready weight.
If he can do it so can you. a manual steering box from a early S10 or malibu fits these cars. aluminum water pump etc etc.. Create a 350 lbs pile of crap you don't need on the shop floor.

 

You can plan on needing a .132 Dyno tested horsepower to weight ratio (7.575 to 1 Pwr/lbs ratio ) to get your ThirdGen into high 11 second ¼ mile ET.
Now weight your car all in with driver.

 

Else save money and buy afr 195’s or equal lol. Make more power and wont need to gut the car and kill street driving ability. 4.56 gear in a 3 spd? Yikes that wont be fun at all

 

Another real simple relatively cheeeeeeeeep option might be, Vortec (96-2000) heads. YYYYYYUUUUUUUUUUJJJJJJJJJJJE improvement over the 50s design.

 

Definitely. I do love the AFRs, definitely not disappointed with the purchase. I think more about changing the cam specs than moving to a different head.

My car was 3450# with iron heads and a 4L60E. I took the AC out and some the emissions stuff. With the T56 and AFR heads maybe its just under 3400# now.

GTA is a heavy thing.

 

Ya it is... Back in the day we used to run around with 5.13's in a hot 327 sbc Chevy II wagon.
Small cid sbc's that are cammed up and moded to go, want to rev up up up. You need the mechanical leverage (gears) to get moving quick.

Its not a diesel engine. Let it rev.. Let it eat.

 

Only need to loose 350 more pounds..😁😁

 

Telling the OP to just get AFR heads or just get Vortec heads does not give him real info on how to go fast while using the 4416 or 081 or 083 cylinder heads.
Any body csn spend lots of money.
This is how you do it on a tight budget using the heads you got on a simple flat top piston 350 YOU CAN BUILD..

The first thing you need to get your head around is all the BLING BLING is not needed and will eat up your $$$. You can do all the modifications and porting Yourself.. You only need to pay for basic machining..

This build does not use roller this roller that etc etc..
It uses a ..525" lift+/- Solid flat tappet cam and stock diameter drop on .550" racing springs pinned studs, stock long slot rockers. example cams Isky 201524, 201534 ,201CC1 Summit Racing CT108. Howards cams have a whole page of cams for this..
It revs up 7000 rpm using just that.
Keep it simple and low cost..

Ya 4.56's are a blast on the street in a low cost light weight hot 350 sbc Street Brat camaro that will have your lunch at a stop light and run 11's at the track.

You $$$ COST / Performance- Fun ratio will be very high.

 

Time is money. There is gonna be a lot of time in making iron heads flow well enough to get into the 11’s. Does the OP even know how to port heads? Its not as simple as taking a grinder to it and removing material lol

save a lot of head aches goin another direction. Its already been established that the iron casting is fine for good hp once properly done but man i wouldnt want to be putting in that time on a grinder on iron.

And weight reduction can be expensive as well, once you go beyond just gutting things. But if ya want a tin can with one aluminum sheet seat, go for it lol you can easily lose 150-200 lbs in interior matting carpeting and seats. If its mostly strip that can work. Just not my thing to do

 

How about a link? Thanks.

 

I actually just bought about 30 minutes ago a nice set of aluminum edelbrock 195cc 202/160 heads that should be a lot better I’m going to do a valve job to clean them up nice and new at my local machine shop that will help me a lot to get the car to 11s like you said and I do need to buy a th350 and also I am going to try to get some 4:11 or 4:56 gears and I’m also buying 275/60 et streets and should be able to keep the car under 3,200 I only weigh 130 I’m very small as I’m sure I’ll grow more

 

I also have an 800 carb for it and I’m am going to buy a Victor jr down the road I have a performer now

 

And as far as weight reduction I’m going to have to weight it I have a trans am so I heard they are heavier than camaros I would probably need to buy a firebird rear bumper and remove the side skirts I know my bumper is pretty light it’s thin plastic I will leave that worst come to worst for weight I can put a sport coupe front clip and I will probably remove my seats besides the drivers I have no ac I am planning on going to no power steering it shouldn’t be too heavy I’ll weight it whenever it’s road ready

 

Good stuff The Edelbrock heads get very good once they are ported..
A good start point.
Try these M/T ET street SS sticky radials.
P255-60R-15 # 3452

What model 800 carb.?
The 11 second ET combo uses the same isky solid cams 10.50:1 cr 4000 stall 9"-10" converter
Vic jr or Holley 300-25 and 4.56 gears.
It will make more power than the ported L98 heads once the Edelbrock heads are also ported..
Its what is behind the bumper covers thats heavy.
The TransAM skirts are light weight. Seats, carpeting sound dampening, heater, door guart beams etc etc.
mw66nova 's car lightening threads as good for info.
My Firebird SE was 3530 lbs w driver. AC delete. full interior.
If you want to use a roller cam instead of a solid flat tappet.. Yhe Comp XSR286R-10 solid street roller
12-772-8 gets it done with 4.56 and 4000+ stall.

 

You can try out both the RPM and the single plane intakes and compare A to B.. In this combo as I layed out for you the single plane will run a bit faster.
You can try out a carb spacer on each.
If the carb is a holley 800 double pumper you are good to go. (4780).

 

it actually is a holley 800 double pumper 4780 and I also have a carb spacer too