Anyone running an AFR headed LT1?
Registered User
Joined: Jun 2002
Posts: 471
From: Evansville,IN,USA
Originally posted by engineermike
Yes, the 11.09 pass was NA. My 1/8th mile speed was 94.9, so yours was only about 4 mph slower than mine, which is only about 40 hp difference (yes, this rule applies to 1/8th mile speed also).
You don't mention your compression ratio. Compression ratio is critical in building a strong naturally aspirated engine. An engine can gain or lose 5% power per full point in compression ratio.
You also don't mention your intake set up. It isn't tuned port, is it? If so, there may be the problem.
Do you have legitimate flow numbers on the heads (actual test numbers, not vendor advertised numbers)?
Finally, I had a 3200 Vigilante, which is an excellent converter, and 3.73's, versus your 2800 and 3.23's. My best 60' was in the 1.55 range. I suspect yours wasn't that quick 60', especially with the Pep Boys radials.
Mike
Yes, the 11.09 pass was NA. My 1/8th mile speed was 94.9, so yours was only about 4 mph slower than mine, which is only about 40 hp difference (yes, this rule applies to 1/8th mile speed also).
You don't mention your compression ratio. Compression ratio is critical in building a strong naturally aspirated engine. An engine can gain or lose 5% power per full point in compression ratio.
You also don't mention your intake set up. It isn't tuned port, is it? If so, there may be the problem.
Do you have legitimate flow numbers on the heads (actual test numbers, not vendor advertised numbers)?
Finally, I had a 3200 Vigilante, which is an excellent converter, and 3.73's, versus your 2800 and 3.23's. My best 60' was in the 1.55 range. I suspect yours wasn't that quick 60', especially with the Pep Boys radials.
Mike
Intake is a holley street dominator high rise dual plane, holley 750 DP
The heads are advertised at 289/195@.700, no I have not had them flowed myself
I have an ACT 9.5, dana at probuilt said that anything over 3.42's would hurt my times
my 60 ft is 1.84 on the pep boy tires
I have not done any tunning, jet changes, timing curve, nothing
Yes I need suspension work, the car feels like its doing the mexican hat dance off the line.
I have thought about going with a bigger extreme roller cam, which would require me getting more stall and more gear.
There's alot for me to do with the car before I consider a cam sway.
I am super impressed by a 11.09 on motor. that is flat out hauling a$$
Registered User
Joined: Feb 2000
Posts: 787
From: AUSTIN (Georgetown), TX
I am using AFR 190 LT1 heads. They have been ported and polished and flow between 285-292 cfm @ 28". Works pretty well. I will be selling these to upgrade to 220's or so. Times in the sig.
Tony Shepherd
Tony Shepherd
Registered User
Joined: Jun 2002
Posts: 471
From: Evansville,IN,USA
Was your tranny a TH350 or 700R4, I know you said you had a vigilante TC so I am assuming its a 700. Did you have a transbrake or just foot braking it? What about suspension mods, cage? LCA? brackers? slicks?
Ever since I read your post I think my car should be way faster than what it is. I had looked at the 294xtreme roller cam, but my engine builder didn't think that I would notice that big of a difference and should go to a solid roller. I don't wanna spend the money to go to a solid roller right now. Fist off I have lots of other things to work on before a cam swap. What's your opinoin on the 3.73's being to much? I am running 90.4mph with 3.23's and a 2800stall, it stalls at 3000 when the tires hook. well kinda hook.
Hell, most of the cars out there aren't running 11.09's on spray let alone motor.
Ever since I read your post I think my car should be way faster than what it is. I had looked at the 294xtreme roller cam, but my engine builder didn't think that I would notice that big of a difference and should go to a solid roller. I don't wanna spend the money to go to a solid roller right now. Fist off I have lots of other things to work on before a cam swap. What's your opinoin on the 3.73's being to much? I am running 90.4mph with 3.23's and a 2800stall, it stalls at 3000 when the tires hook. well kinda hook.
Hell, most of the cars out there aren't running 11.09's on spray let alone motor.
Registered User
Joined: Mar 2002
Posts: 2,743
From: Baton Rouge, LA, USA
I had a 700R-4, left off the foot brake, stock LCA's with poly bushings, no cage, and drag radials.
It occurs to me that you think there is a problem with your chassis set-up. A chassis set-up will help your 60' time, but not your speed, which is down about 4 mph from mine.
My line of thinking is to get the speed where it's supposed to be, then worry about launching it. Getting a car to leave is the easy part (at least when your in the 11's).
I'd stay away from a solid roller unless you're trying to run mid 10's. Plus, a full solid roller conversion is around $1000. I fully believe it's possible to run 10.70's NA with a hydraulic roller, assuming the cam is right and the valvetrain is set up right. Extreme hydraulic roller cams require 140+lb seat pressure to work right. THIS IS VERY IMPORTANT!!! I'm running 145lb in my current set-up.
Upgrading to the 294 cam will gain you about 12 - 15 hp. If it's worth it to you, then go for it.
A car will run best with a gear that redline's the engine at the end of the quarter mile. I had 3.73's and 26" tall tires, which made the motor turn 6,100 through the lights. This is very close to optimal, since I shifted it at 6,200. Also, the Vigilante 3200 (aka: 6 pump) is a very good converter that I also attribute my good times to.
You stand to gain about 15 - 20 hp by raising you compression ratio to 11/1. If you raise your compression, you really need to upgrade to the 294 so it will not detonate. These two mods go hand-in-hand.
So, deck the heads to get the compression to 11/1, get a quality full-radius valve job done as well as some minor bowl work and chamber de-shrouding, set up the valve springs at 140 lb seat pressure, get the 294 cam, jet the carb on a WBO2, set the total timing at 35 degrees (vacuum advance unhooked), get a Vigilante 6 pump, and switch to 3.73's and you should be there.
You'll find that, in this stage of the game, the details become very important.
Mike
It occurs to me that you think there is a problem with your chassis set-up. A chassis set-up will help your 60' time, but not your speed, which is down about 4 mph from mine.
My line of thinking is to get the speed where it's supposed to be, then worry about launching it. Getting a car to leave is the easy part (at least when your in the 11's).
I'd stay away from a solid roller unless you're trying to run mid 10's. Plus, a full solid roller conversion is around $1000. I fully believe it's possible to run 10.70's NA with a hydraulic roller, assuming the cam is right and the valvetrain is set up right. Extreme hydraulic roller cams require 140+lb seat pressure to work right. THIS IS VERY IMPORTANT!!! I'm running 145lb in my current set-up.
Upgrading to the 294 cam will gain you about 12 - 15 hp. If it's worth it to you, then go for it.
A car will run best with a gear that redline's the engine at the end of the quarter mile. I had 3.73's and 26" tall tires, which made the motor turn 6,100 through the lights. This is very close to optimal, since I shifted it at 6,200. Also, the Vigilante 3200 (aka: 6 pump) is a very good converter that I also attribute my good times to.
You stand to gain about 15 - 20 hp by raising you compression ratio to 11/1. If you raise your compression, you really need to upgrade to the 294 so it will not detonate. These two mods go hand-in-hand.
So, deck the heads to get the compression to 11/1, get a quality full-radius valve job done as well as some minor bowl work and chamber de-shrouding, set up the valve springs at 140 lb seat pressure, get the 294 cam, jet the carb on a WBO2, set the total timing at 35 degrees (vacuum advance unhooked), get a Vigilante 6 pump, and switch to 3.73's and you should be there.
You'll find that, in this stage of the game, the details become very important.
Mike
Registered User
Joined: Jun 2002
Posts: 471
From: Evansville,IN,USA
I am kinda stuck where I am at with the compression ratior, I have iron heads. I don't know my total advance right now, nor have I made any jet changes. I will probably get a performance distributer in the spring. I am running a stock HEI dist with MSD 6AL and the HEI conversion. My friend put a summit dist in his poncho 455 with the same setup as mine and picked up 4mph, thats because the old HEI was junk. I don't expect to pick up that much if anything.
Do you think the vigilante is really that much better than the ACT? I went with the ACT because it was about 250 bucks cheaper than the vigilante.
Yeah I hope to pick up some time with suspension mods, but not any mph.
When I cross the line I am winding out 2nd gear. I can ether shift at 5800 or hold it out will 6100 or so.
I hope with some dyno tuning I can pick up maybe 1-2 mph. we will have to see.
It amazes me that you run so much faster than I do and with a smaller engine. You must have built a better combonation that I did.
Thanks again.
Jason
Do you think the vigilante is really that much better than the ACT? I went with the ACT because it was about 250 bucks cheaper than the vigilante.
Yeah I hope to pick up some time with suspension mods, but not any mph.
When I cross the line I am winding out 2nd gear. I can ether shift at 5800 or hold it out will 6100 or so.
I hope with some dyno tuning I can pick up maybe 1-2 mph. we will have to see.
It amazes me that you run so much faster than I do and with a smaller engine. You must have built a better combonation that I did.
Thanks again.
Jason
Registered User
Joined: Jun 2002
Posts: 471
From: Evansville,IN,USA
Originally posted by engineermike
I used a stock, Autozone HEI, no MSD box.
With torque converters, you get what you pay for. But without good tires, you might as well use the stock converter.
I used a stock, Autozone HEI, no MSD box.
With torque converters, you get what you pay for. But without good tires, you might as well use the stock converter.
how many people you see cutting 1.84's with stock conveters?
Registered User
Joined: Apr 2002
Posts: 247
From: Wichita, KS
Originally posted by engineermike
AFR's are great, but stay away from the 190/195 heads. They don't flow what they are advertised to. AFR says 262 cfm, Thunder Racing's flow bench says 233 - 240 cfm.
But the 210's are a different story (I'm on my second set now). AFR says 285 cfm and the flow bench says 280 - not bad realistically.
My opinion is 210's on a 350 or 383 and 220's on a 396 and up.
My last car ran well with 210's and no blower / no nitrous. Here's the combo:
'89 Firebird coupe, 700R4, Vigilante 3600, 3.73 gear, drag radials, 3550 lb with me in it.
11.3/1 compression 383, 5.7 rods. Pump gas: no problem.
AFR 210's out of the box.
GM 847 hydraulic roller cam (296/304 advertised, 234/242 at .050).
Victor Jr. intake and Holley 750 carb.
SLP 1 3/4" shorty headers, SLP muffler.
This car ran a best of 11.09 at 122.7 mph, which equates to about 440 rwhp, or about 530 at the crank.
I sincerely believe there was more power available in the combination. It had a little 2 1/4" y-pipe, which was probably restricting the exhaust. Plus, the shorty headers aren't as good as LT's. Finally, the cam was a conventional hydraulic roller. A Comp Extreme cam that's 294/300 advertised or 242/248 at .050 would not have idled any worse, but would have made more power.
Mike
AFR's are great, but stay away from the 190/195 heads. They don't flow what they are advertised to. AFR says 262 cfm, Thunder Racing's flow bench says 233 - 240 cfm.
But the 210's are a different story (I'm on my second set now). AFR says 285 cfm and the flow bench says 280 - not bad realistically.
My opinion is 210's on a 350 or 383 and 220's on a 396 and up.
My last car ran well with 210's and no blower / no nitrous. Here's the combo:
'89 Firebird coupe, 700R4, Vigilante 3600, 3.73 gear, drag radials, 3550 lb with me in it.
11.3/1 compression 383, 5.7 rods. Pump gas: no problem.
AFR 210's out of the box.
GM 847 hydraulic roller cam (296/304 advertised, 234/242 at .050).
Victor Jr. intake and Holley 750 carb.
SLP 1 3/4" shorty headers, SLP muffler.
This car ran a best of 11.09 at 122.7 mph, which equates to about 440 rwhp, or about 530 at the crank.
I sincerely believe there was more power available in the combination. It had a little 2 1/4" y-pipe, which was probably restricting the exhaust. Plus, the shorty headers aren't as good as LT's. Finally, the cam was a conventional hydraulic roller. A Comp Extreme cam that's 294/300 advertised or 242/248 at .050 would not have idled any worse, but would have made more power.
Mike
Registered User
Joined: Mar 2002
Posts: 2,743
From: Baton Rouge, LA, USA
210's do not kill the low-end of a 350 cid motor. Been there, done that, and it worked fine.
I've seen dyno tests that show around a 10 ft-lb loss in low-end by using 210+ cc intake ports on a 350.
You won't even notice the loss.
And if you're willing to spend some bucks on porting, you might as well port the stock heads, as they have 290 cfm potential in the right hands.
Mike
I've seen dyno tests that show around a 10 ft-lb loss in low-end by using 210+ cc intake ports on a 350.
You won't even notice the loss.
And if you're willing to spend some bucks on porting, you might as well port the stock heads, as they have 290 cfm potential in the right hands.
Mike
Registered User
Joined: Mar 2002
Posts: 3,082
From: San Juan PR
Race prep is apparently doing some nasty work on the lt4 215 aFRs... I am intrigued by their heads...
My car did 555rwhp with 8psi and I wonder if that was good enough for the 190lt1 heads that I have... I am not sure what my heads flow, but they shouldn't be THAT bad for the power it made...
I have raced and beaten w/o problems 590rwhp Rx7 turbo II that did 10.6@131mph from 25 roll to 145 and he got a 2 car head start and I beated him by 3 cars... so it means they are making the power... all this with 10psi of course not 8
My car did 555rwhp with 8psi and I wonder if that was good enough for the 190lt1 heads that I have... I am not sure what my heads flow, but they shouldn't be THAT bad for the power it made...
I have raced and beaten w/o problems 590rwhp Rx7 turbo II that did 10.6@131mph from 25 roll to 145 and he got a 2 car head start and I beated him by 3 cars... so it means they are making the power... all this with 10psi of course not 8
Registered User
Joined: Mar 2002
Posts: 3,082
From: San Juan PR
Originally posted by engineermike
210's do not kill the low-end of a 350 cid motor. Been there, done that, and it worked fine.
I've seen dyno tests that show around a 10 ft-lb loss in low-end by using 210+ cc intake ports on a 350.
You won't even notice the loss.
And if you're willing to spend some bucks on porting, you might as well port the stock heads, as they have 290 cfm potential in the right hands.
Mike
210's do not kill the low-end of a 350 cid motor. Been there, done that, and it worked fine.
I've seen dyno tests that show around a 10 ft-lb loss in low-end by using 210+ cc intake ports on a 350.
You won't even notice the loss.
And if you're willing to spend some bucks on porting, you might as well port the stock heads, as they have 290 cfm potential in the right hands.
Mike
Registered User
Joined: Mar 2002
Posts: 2,743
From: Baton Rouge, LA, USA
We flow tested some at Thunder Racing.
The Competition heads outflowed the Race Ready's by about 5 - 10 cfm from .200 - .400 lift. They flowed the same at .500". At .600 and .700, the Competitions did about 10 - 15 more cfm.
Personally, I'd get the Race Ready's, then have a QUALITY valve job performed and blended into the bowls and chamber. A shop will typically charge $250 - $300 for this work and they should pick up 10 - 15 cfm throughout the range. The AFR valve job isn't great.
Mike
The Competition heads outflowed the Race Ready's by about 5 - 10 cfm from .200 - .400 lift. They flowed the same at .500". At .600 and .700, the Competitions did about 10 - 15 more cfm.
Personally, I'd get the Race Ready's, then have a QUALITY valve job performed and blended into the bowls and chamber. A shop will typically charge $250 - $300 for this work and they should pick up 10 - 15 cfm throughout the range. The AFR valve job isn't great.
Mike