u r sofa king we tah did

i just got me a set of iron tpi heads for free fifty so im gonna see what kinda results i can get out of them (hell you cant beat the price). i just ordered a few parts for the heads, heres what the setup is going to be:

intake valve: manley race flow 2.02
exaust valve: manley race flow 1.60
valve springs: comp cams 1.437 safe to .550
spring retaintes: comp cams titanium
valve locks: comp cams 10 degree locks
rocker arms: comp cams 1.6 full roller
rocker studs: screw in 3/8

i have a dyno day setup on the 4th of may with some other guys in north texas so i will definately post results. i also hit the track a couple times a month so ill post trap speed increases before the dyno numbers come in. i hope to have these heads done and installed in 2-3 weeks, depending on time.

ImportsRsloths

If money is an issue and if you havent bought the parts yet, I would really look at the trick flow heads that are like $900..... cause its gonna cost a LOT for the machine shop costs and the parts.... you might end up having hopped up iron STOCK tpi heads compared to aluminum bad @$$ aftermarket heads with just as much hop up-age for about the same $$$$$ your call.....

u r sofa king we tah did

money isnt the issue, its just the heads were free, and you cant beat free heads ya know? plus i just ordered all that stuff i listed this morning so no turning back now. plus if i dont like the performance i get out of these i can always buy a set of bare AFR 190s and throw all of the valve train setup i just bought on em. plus for some reason i just dont like TFS, just a personal issue i guess. oh and the cost of this is about half, if not less, than a set of assembled TFS G2s since im doing the work myself.

Vader

Sofa King,

Here are some steps I've done in the past with reasonable success:

1. Get the valve bowls opened up as much as the seats will allow.

2. Cut down the short side radius around the valves as much as possible.

3. Reduce the diameter of the valve stem bosses in the bowls to a minimum and taper them back to the top of the bowl.

4. Raise the position of the intake ports at the manifold side as much as you can while still mating the intake base and allowing enough flange for a gasket.

5. Blend the larger intake manifold ports as straight and far back to the bowl areas as you can - you want to be able to see as much of the back side of the valve from the intake port as you can.

6. Straighten out and enlarge the exhaust side as well, and really try to cut down that short-side radius there since it is terrible on stock heads.

7. Make a larger "D" out of the ports. Polish everything on the exhaust side to a mirro-like finish, and polish the chambers without enlarging them.

8. When you get a pair of ports done to your satisfaction, make a set of templates that fit the contours exactly. Old playing cards and scissors are all that's necessary, then make photocopies or scan the images so you can reproduce them when the templates get worn down or damaged from use. Make all the rest of the ports conform to these templates and you should have a pretty well balanced flow on each cylinder. (I wouldn't mind gettng a set of those templates from you as well. )

9. Ask around about cutting a radius on the FACE side of the intake valves to improve flow around them. It is reported to work better than a multi-angle valve seat grind for improving flows. The circle track guys around here are gaining 5HP by doing that on 800HP engines with iron heads.

When you're all done, you should have increased the intake port volumes from just under 170cc to around 198-200cc. You can stretch it a bit more, but the castings tend to get a little thin in some areas when you get greedy, unless you want to nickel weld the thin areas between the runners and go hog-wild.

Just some random ideas.

u r sofa king we tah did

i take it youve been here, done that. what did you do about that hole where the rocker stud is cast? someone told me to jb weld the hole, but i dont know if id jb weld a cylinder head, i might carefully break out the welder.

Vader

Sofa King,

I'm with you. JB Weld is a band-aid to me. It might be great in a pinch, but not as a permanent repair, and I'd never use it INSIDE an engine unless I didn't care about the car.

The LT1/4 heads have the same holes (right down into the intake runners). After you tap for screwed studs, you can insert a phosphor-bronze or beryllium-copper bolt to the same depth as the studs and weld the bottom closed with nickel filler. I guaranty it will be eleventy-thousand-jillion times better than JB Weld. I'm not sure I'd want a chunk of metal-bearing epoxy (JB Weld) falling out of the hole from the unequal rates of thermal expansion and getting stuck in a valve until the piston top pounds it back in to place. Yuck...

And nickel bonds with cast iron so well, and creates a very nice, machinable surface. You'll never even know it's there.

IROCZTWENTYGR8

iTrader: (1)

What kinda power can u get out of ported and polished L98's??

u r sofa king we tah did

no clue, wait until may 4th and ill post exact numbers.

87transam5.7tpi

I've heard 20hp, but I HIGHLY doubt that. also you don't want to polish your intake runners and bowls. because the roughness mixes fule better. so port the intakes, and port AND polish the exhaust.

Josh

IROCZTWENTYGR8

iTrader: (1)

Cool. I will.

DANIELEK

20 HP? I am hoping for at least that when I do my heads in a month or so.

IMO, if you do all that Vader suggested plus going with bigger valves from Manley, you can get at least 20 HP from a properly tuned engine, assuming that you have takes care of your restricted exhaust system.

u r sofa king we tah did

yeah im expecting way more than 20 horses with the oversize lightwieght valves, and all the goodies. id expect around 20 horses just from cleaning up all the casting flaws and polishing the exaust. anyone know about how much it costs to get heads flow checked? id kinda like to know the flow #s too...

87transam5.7tpi

I can't find anyplace in nebraska that will flow heads. that really sucks. so I'm gonna build my own. see how that works out, I got a couple of articles from a guy on here. if anybody wants em give me an email or PM

Josh

rhuarc30

I should be porting a set of stock iron L98's in the next week or 2, and I have flowbench access so I'll flow em for you. Bear in mind that this will be a full blown port job and not just a minor clean up. I've ported these heads before to support 450 hp before, but your actual gains will depend on your other components. But to give you a rough guestimate for now I usually get an improvement of 32-38% on the intake and 42-47% on the exhaust (depending on what heads we start with as well, some port better tahn others). With the stock flow numbers

Lift/Intake/Exhaust
.100 44 41
.200 101 82
.300 155 125
.400 182 137
.500 196 140

That works out to 259 intake and 199 exhaust at .5 lift using the low percentages. I usually see even larger improvements in the low lift flow and upgrading the valvetrain to handle higher lifts will help as well. Bumping up to the .55 to .59 range can get you another 15 -25 intake 8-14 exhaust.
Hope this helps you guys out. I'll post the flow numbers when I get 'em. If I have time I'll flow 'em after each thing (valve job etc).
John
Btw using AFR's formula for how much hp the heads will produce, the stock heads will support around 400hp and heads ported like I've described will support over 500 hp with everything optimized for the combination.

Vader

I would hope so. On stock cast iron LT1 heads, I ported as described and installed Manley Race-Flo valves, lightweight 10° retainers, LT4 springs, and gained 60.2 HP and 51.9 ft/lb at the rear wheels. This was with a Comp XR-266HR-14 installed at the same time. The engine now has the XR-276HR-14, but my dyno source is no longer in business due to some misunderstanding with the government over something about "failing to report and register the sales of some used Corvette parts, and the subsequent failure to claim that income" - or something like that.

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rhuarc,

It would be interesting to see some of your flow comparisons when finished.

I guess I'm somewhat an "old-school" kinda guy, but I remember back when there was no such thing as aftermarket heads, and guys were making plenty of power with welded/ported stock castings. I still believe there is a lot of power left there by the imperfections and compromises of the mass-production process, and all we have to do is go out and grab it. People are too quick to discard factory castings as "inferior".

u r sofa king we tah did

plus you cant beat the price of the cheap/free stuff that makes power.

ImportsRsloths

I got brand new World Products S/R torquer heads (2.02/1.60) heads that have a $400 port job done at a machine shop (best porting job on cylinder heads i have ever seen)..... I got them for a steal of $400 off of this site about 5 months ago........ gotta look around for the deals!!! BTW the guy let them go cheap cause he bought AFR 190's instead

u r sofa king we tah did

do you make good power with those world product heads?