KBRVETTE93

What is the difference in horsepower between a decent set of reworked LT1 heads and the stock AFR 195s?

P.s. LT1 intake, larger TB and injectors headers, cam and stoked to 383


For a car seeing 4-5 track weekends and street use does the HP difference make sense in cubic dollars?

STL94LT1

How much $$ are you willing to pay? As much as I like the new AFR Eliminators, I have seen some great performing ported stockers.

93cruiser

How much $ will you have in the ported/rebuilt LT1 heads? When I compared the money, it was really close to the cost of the afr's. BTW, when you compare the LT1's to the afr's there is no comparison. The afr casting allows for a full size intake port. The difference is in the push rod tunnels. The LT1 casting has huge pushrod tunnels that interfere with the intake port. No way of grinding this out without cutting thru the wall. Just my 2 cents.
93cruiser

cv67

Dont let anyone tell you they will be "just as good as", theres no way.
Why spend the money for a nice motor and then shortcut the most important part? Forget old heads, get the good stuff.

Cost of

valves/seats/keepers/retainers/cups
labor-clean, mag, setup install height etc
guides?
valve job
porting
flow bench time to prove whats there
surface

Any shop that doesnt do/check all this is wasting your time and $.

Ported stockers have their place but on a stroker where youre looking for more go for the good stuff right off the bat, plus its all new, lighter valvetrain, thicker deck, etc. I have no horse inthe game just being honest here.

KBRVETTE93

My guy is saying about $500 to port and replace valves and springs. Says that he can make around 400hp the crank. I would like a bit more hp (of course) and still want to have a car I can enjoy driving. Love my C4.

We're going with a forged rotating assembly. I want a "balanced" finished product.
If I stay with the stock LT1 intake does it still make sense to step up to the AFRs?

cv67

You should do the stock intake regardless, it doesnt take much and will make good gains, Id have my doubts on $500 getting a good port job and all new hardware. I know everyones got to stick to a budget just hate to see anyone disappointed or having to do it over twice.

KBRVETTE93

Have my guy port the stock LT1 intake and purchase a set of eliminators? = a HP gain of_________ ? cost a total of?__________

I'm beginning to lean hard toward the AFR 195. Explain the benefit of the eliminator, please.

96 lt-4

I would port match the intake to the head and leave it alone.With the 383 you should see 400 to the wheels even with a mild cam..........if you use the AFR heads.Sell your stock ones and buy the AFR heads.It is a better design and will let your motor move the required air out of the box.
Just my opinion.My 383 LT4 just made 441 at the wheels with mildish cam and AFR heads with a stock(gasket matched)LT4 intake.

BrianCunningham

I started off going with ported stockers for my blower build

It wound up being cheaper just to get a new set of AFR's

add up the whole build, porting, new valves? guides? recut the seats?

Red Rocket

[QUOTE=KBRVETTE93;1572568521]Have my guy port the stock LT1 intake and purchase a set of eliminators? = a HP gain of_________ ? cost a total of?__________

25LBS of torque - 30-50HP. Net cost of $2600-$600(reworked LT1 heads)- $250(new springs) - $400 (sell old LT1 heads) = $!,350.00
for stroker.

JAKE

A recent LT1 cylinder head SHOOT-OUT in their mag and posted on their site, GMHTP, showed the results of a pair of Eliminators Vs a pair of CNC ported LT1s and the power levels were surprisingly close, like AFR winning by 21 HP and 17 ft/lb of torque at 6K.

Remember, though, that LT1 heads were only 185cc Vs AFRs 195s. IIRC 514 HP Vs 493, on the same 383 etc. So considering cost differences and goal, ported LT1s could be a good option.

How much is 21 HP really worth; dollar amount per HP?

BTW, TrickFlows came in 2nd.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

cv67

Id like to see the differences at 6500 and 7k, bet its substantial.

Cost? A nice LTx head done up by A.I. isnt cheap, they do an all out job. Havent checked recently but I was under the impression by the time the core charge/ship/tax is all said and done they were around 2k?

STL94LT1

~8 years ago I had my stock heads CNC ported, larger valves, bronze guides, springs/retainers/locks, and the cost was $1500. It's not cheap to get the full meal deal done on the stock heads.

cv67

More than lilkely you had them done right so money well spent. Most port, throw a cheap spring on, might or might not get a cheap valve job and hold their breath on the rest.

STL94LT1

My heads were ported by CNC Cylinder Heads. I have read good and bad reviews on their porting services. But, the last time out at the track my stock shortblock LT1 ran 4 ~119 mph runs. That seems to compare to some of the best heads of even today.

Red Rocket

Had ported LT1 heads by TPIS ($1200)which MTI reworked in 2002($300) with the upgrade of my 350 to a 396. Lloyd Elliott quoted me $600 to do more porting this year. He felt 275-280CFM was possible. MTI's flow sheets were 262CFM in 2002.

Car dyno'd at MTI in Houston at 409RWHP/415RWTQ in 2002. Horsepower at 6500 RPM's was 370RWHP. Torque at 3000 was 375RWTQ at 6000 350RWTQ. Car ran pretty consistent 11.6's at 122MPH's in 1/4 and 7.4's at 96MPH in 1/8 the past 7 years.

With the AFR 195cc Eliminator Competition head upgrade and ported LT1 intake this year, the car now dyno's close to 440RWHP/440RWTQ on a very rich mail order tune. The tuner feels we will be at 465-470RWHP with the dyno tune next month which is in line with other similar set up's. Today the horsepower at 6500RPM's is 430RWHP. Torque at 3000 is 398RWTQ at 6000 it is 400 RWTQ.

My goal was to knock off .2 off my ET so I could run year round in the Pro Class/bracket racing even in the hot summer Texas months. No doubt Lloyd Elliot's porting would have added to the original numbers numbers as well.

As noted above, I felt spending the net of $1350 for the AFR competition heads was worth it. The GMHTP article was for the street heads FWIW.

88BlackZ-51

do you have that link jake?

KBRVETTE93

Thanks guys! This comparison is exactly what I was fishin for. I will keep everyone posted on my choice.

reoch999

Between the new valves, guides, seats, and machine work, I payed about $500 to my machine shop and that was with no real port work. They did a little deshrouding, and did a very nice valve job for me, but any port work I wanted would have been way more. I did that myself, and bought and installed the new springs myself too. On a side note, I would NOT advise doing the port work yourself to save a buck. I did it for the experience because it was something I was curious about, but it's a long tedious job and gets aluminum powder EVERYWHERE. I would have been better off sending them to LE. I'm sure he could have done a much better job anyway. A nice set of AFR 195 heads is still on my wish list. And so is that forged 383 rotating assembly you've got.

As for the 400 crank horsepower number, I'd be pretty disappointed with a 383 LT1 with that kind of output. My stock bottom end with a camshaft and home ported heads is in that neighborhood. I'd expect at least 450 at the crank (~360rw) from that engine with a very mild cam. 500+ (~400rw) with the right heads and cam.

reoch999

Good to see you back.