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In the shop with my Vette
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Ok gang. I know this is no easy task. ( I know I asked about this years ago, but let's do this) But I want my 10.65:1 compression 496 bbc to drop over a half a second. I need to keep the current cubic inch, and compression. And I am not installing a power adder. My car is light, approximately 2700 pounds give or take a few with me in it. It is a 4-link coil over deal, basic bracket style build. And I race in southern & western Kansas where the spring and summer air is
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total shit. Up to 6000 ft at the worst part of the summer. I know this ET will most likely only be attainable in fall when our air drops to around 1500-2000 feet. Currently the car has a best ET of 9.64 @ 132 mph. But has been 139. On its best ET run it did a 1.32 60'. But my last pass down the track it went 1.30 @ 9.77. & 135 mph. I changed headers, and it killed a bunch of mph at every incremental. (Had Lemmons, and went to Chinese side pipes, I am switching back to the Lemmons) I attribute the improved 60' to front travel limiters. This car wanted to stand on the bumper a few times) and did a 1.34 on the back tires once.

Current combo is as follows, but Chris Straub is cooking up a new cam for me now. Maybe he will chime in with the specs if he has them. His cam and valve train package is what I WILL BE RUNNING.

496 BBC
Lunati 4.25 crank
Molnar 6.385 rods
SRP 18 dome pistons w* 1/16 1/16 & 3/16 low tension rink pack, 0.00 deck height
Canfield 310 heads with 2.30 & 1.88 valves, bowl blend and gasket match only, done by Canfield
Edelbrock Victor Ram II with Pro system 950's
Aeromotive Vacuum pump
Stefs oil Pan with rear sump and passenger side kick out
Current cam is a .744/.714 278/288 4-7 swap on a 113 LSA (new cam from straub coming, I do not yet have specs)
Old cam the motor would only crank @ 145-150 PSI

Trans is a stock planetary TH400 with a chance converter 5800 rpm launch, I have a 2 step to dumb it down if need be
4 link & coil over rear, currently 4.86 gears, running with a 29.5 X 11.5 W tire. I've had a 32 tall tire on it, and that is the 139 mph pass. But they rubbed so I switched back. The 29.5 tire on the 9.64 pass, I was on the 7600 limiter for over 3 seconds. So I will be switching to whatever gear I need, Maybe a 4.30? I have a set of 4.56's from Dad I can use it that's enough.

Now, my best times are my off the trailer times. I have done 0 track tuning on this thing other than installing the front travel limiters. Kept the timing @ 38, ran on 91 pump gas. I know with a new combo, I can play around with timing, jetting and suspension and find gains. But I was just having fun with the car as is. I feel like the 116 mph to the 1/8 should be able to find a 9.30 as it was. But I took the leap, and want to get aggressive with go fast with this thing.

Some upgrades I am looking at now...
I have a Steffs fabrication oil oil pan. I'm looking at upgrading the oil pan to a full sump, double kickout unit PN 21600 from moroso. Front crossmember is a non issure for this pan on a C3 corvette.
I have an aluminum drive shaft. I know that's probably negligible, but every little bit counts. That's about a 10-15 pound weight savings. I can lose another 20 by going to a light weight battery.
Getting the intake and heads ported. Intake is box stock, so a few bald eagles may be unlocked there.
I know with changes like this there are no huge grand slams. But I also know every tiny bit can add up to a number. I'm guessing the engine is around 750 hp and low 600 torque, or high 5XX. Probably not a torque monster with the long duration, and wide LSA. Straub and I talked about power and torque potential of the combo, but I know that is an educated guess.
Power glide trans? I know they are much lighter, is that a good choice? I never wanted to give up the low first gear before, because I knew my engine was no torque monster. But with the revamped combo it will probably make much more torque and pull that longer first gear better than before.
So if any of you guys have any suggestions, or proven methods for a similar situation I am all ears.

Thanks!!!
 

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You're way off on hp estimates. Wallace racing said 600 crank horse with [email protected] Something's amiss in combo. Cam/carbs would be my first guess. If you're on the limiter that long change gears first though, I'd say 4.30s.
 

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With 9.64-9.77 at 2700lbs, yer not making 750HP unless you're throwing 150hp away every pass.

Need more info on heads and need to see time slips to make better judgments.
Do you have data acquisition on your hot rod?
Is 8.90 for index racing or just want to run sub 9's?
 

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That combination should make well over 800hp. I've ported a LOT of Canfields and there are fundamental changes that need to be made in order to make them work. It's all in the short turns and bowls. My 467 with that same top end and a 2.25 valve, 12.4:1 cr made 821hp. The 2.3 valve is only good for a little over 7000rpm.
 

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First I would suggest that you may want to go back to your current set up at some point. After you spend all the $$ to upgrade your current engine, you may not get to where you want with those reworked , intake heads and new pistons. If it were me, I would continue using your current set up until you can have professional engine built at 496" that will do what you want. Then remove the current engine and trans and cover it up in the corner of your garage after removing rocker arms and spraying down with fogging oil. Take your new cam to the PRO you choose and have him spec an engine that will go faster than 8.90. Buy a GOOD PG trans and converter for your new engine. If you can't afford to do this, rethink your plan. JMO.
 

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In the shop with my Vette
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Discussion Starter #6
You're way off on hp estimates. Wallace racing said 600 crank horse with [email protected] Something's amiss in combo. Cam/carbs would be my first guess. If you're on the limiter that long change gears first though, I'd say 4.30s.
I may very well be off on the HP estimates. But also remember I put 0 effort into optimizing this combo. It came off the trailer with a baseline engine/chassis tuneup in it. And that's the way I raced it until now. I'm pretty sure there is a 9.30 or a 9.20 in it in good air and with proper optimization as is. But that is speculation.
 

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Hey Hitch...At your weight you'd be better off with a glide.you need 750 ish to get into the 8s at 2700. Your 60 seems a little slow.if your 116 in the eighth your giving up bad on the back end to only run 135,should be at least 143-44.
 

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In the shop with my Vette
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Discussion Starter #8
First I would suggest that you may want to go back to your current set up at some point. After you spend all the $$ to upgrade your current engine, you may not get to where you want with those reworked , intake heads and new pistons. If it were me, I would continue using your current set up until you can have professional engine built at 496" that will do what you want. Then remove the current engine and trans and cover it up in the corner of your garage after removing rocker arms and spraying down with fogging oil. Take your new cam to the PRO you choose and have him spec an engine that will go faster than 8.90. Buy a GOOD PG trans and converter for your new engine. If you can't afford to do this, rethink your plan. JMO.
A whole new engine and trans is definitely not in the budget. This engine is about 10 years old, and has less than 12 runs and about 100 street miles since a freshen up with the new cranks and rods. Everything was done at professional shops. Although the shop the shop that just did the rebuild did not provide any of the new hard parts. I brought him the new crank, and rods. Everything else he used from the original build. This combo is going to get upgraded, and if it cannot go 8.90 that's no big deal. I'm really just ET chasing. It's is just my ego that wants it to go that number. Are you recommending new pistons for something with a thinner ring pack?
 

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In the shop with my Vette
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5,054 Posts
Discussion Starter #9
Hey Hitch...At your weight you'd be better off with a glide.you need 750 ish to get into the 8s at 2700. Your 60 seems a little slow.if your 116 in the eighth your giving up bad on the back end to only run 135,should be at least 143-44.
It was down on mph because it was on the limiter. I could have thrown a higher RPM chip in it, but I didn't feel like beating on it that hard. I feel like the current combo can go 1.28 60'. But I have never spent the time to optimize it. When it did the 1.30 60' it did roll the tires over a couple time leaving the line. All other passes it was doing 1.32ish off the brake, but pulling tall long wheelies doing it. So I attribute the limiters keeping the front end down to the improved 60'.
 

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First I would suggest that you may want to go back to your current set up at some point. After you spend all the $$ to upgrade your current engine, you may not get to where you want with those reworked , intake heads and new pistons. If it were me, I would continue using your current set up until you can have professional engine built at 496" that will do what you want. Then remove the current engine and trans and cover it up in the corner of your garage after removing rocker arms and spraying down with fogging oil. Take your new cam to the PRO you choose and have him spec an engine that will go faster than 8.90. Buy a GOOD PG trans and converter for your new engine. If you can't afford to do this, rethink your plan. JMO.
Take a custom cam that was designed for this specific combination to a "pro" and have him design a new engine around the cam? :unsure:
 

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In the shop with my Vette
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Discussion Starter #11
That combination should make well over 800hp. I've ported a LOT of Canfields and there are fundamental changes that need to be made in order to make them work. It's all in the short turns and bowls. My 467 with that same top end and a 2.25 valve, 12.4:1 cr made 821hp. The 2.3 valve is only good for a little over 7000rpm.
Scott we need to talk about you porting my heads and intake. I know you guys have a very successful recipe for those heads and intakes on similar cubic inches. If I remember correctly when the original builder flowed the heads he said they only went 347 cfm @ .700. I know this goal is doable with proper planning and execution.
 

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In the shop with my Vette
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Discussion Starter #12
You're way off on hp estimates. Wallace racing said 600 crank horse with [email protected] Something's amiss in combo. Cam/carbs would be my first guess. If you're on the limiter that long change gears first though, I'd say 4.30s.
Also consider I am racing a typical 4500-5500 feet of DA.
 

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In the shop with my Vette
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Discussion Starter #13
With 9.64-9.77 at 2700lbs, yer not making 750HP unless you're throwing 150hp away every pass.

Need more info on heads and need to see time slips to make better judgments.
Do you have data acquisition on your hot rod?
Is 8.90 for index racing or just want to run sub 9's?
I have no data log. All I have is Racer IQ on my phone. And I keep my time slips in a photo album. One thing, I am BAD at making my 1-2 shift without going on the limiter. I finally just bought a C02 kit, and RPM switch to do it for me. Haven't installed it yet though.
 

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Discussion Starter #14
Here's a couple logs. The 9.79 is with the side pipes. And @ about 4000' give or take.
 

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You will need to pick up at least a tenth in just the 60 ft times to get even close to your goal. Your current 60 ft times are what you would expect for a high 9 second car. That is not going to happen with a 4.30 gear. That will for sure slow your car down. To get to your goal you will have to turn that engine much higher RPM than you are now. My car with a flat top 327 super stock engine at 3145 lbs is running 60 ft times same as your car. The short times are where ET is made. I doubt you will be able to get it to 8.90 with your combo.
 

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Discussion Starter #17
You will need to pick up at least a tenth in just the 60 ft times to get even close to your goal. Your current 60 ft times are what you would expect for a high 9 second car. That is not going to happen with a 4.30 gear. That will for sure slow your car down. To get to your goal you will have to turn that engine much higher RPM than you are now. My car with a flat top 327 super stock engine at 3145 lbs is running 60 ft times same as your car. The short times are where ET is made. I doubt you will be able to get it to 8.90 with your combo.
That's cool if it does not. I know that is a stout goal for a pump gas street car.
 

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Discussion Starter #18
RPM is one thing. Build an 8500 rpm motor and get off the limiter. A racepak will help you optimize the package.
The guy that did the last go around said with the current parts it should go 8000 rpm no problem. My balls are just not that big. I guess I could swap pills this weekend, and let it eat ans see how it likes it. But remember I have optimized nothing. There should be a few tenths in tuning alone. And several MPH by not banging on the limiter.
 

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This is just an opinion. Gearing the car up, and going to a glide will kill the 60’ times. I’d turn it to 8,000, have one of this auto gurus redo your 400 trans, and do the SuperStock lightening tricks to it. You’ll gain some there. Then have the heads, and intake done by your choice of head builders, and try it again. You may not get what you want, but it’ll be a sizable gain. And, make sure you have on it a carburetor that actually works.
 

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The guy that did the last go around said with the current parts it should go 8000 rpm no problem. My balls are just not that big. I guess I could swap pills this weekend, and let it eat ans see how it likes it. But remember I have optimized nothing. There should be a few tenths in tuning alone. And several MPH by not banging on the limiter.
I would pull the high side chip out. I never run one in my car. The last thing I want is the engine hitting the rev limiter in high gear at the big end. Hitting the high end rev limiter is much harder on the engine than just turning the RPM. Also lugging the engine with the wrong gear ratio is also an engine killer. The only thing you have to be concerned about when turning one up is to make sure you have enough valve spring pressure. You don't want things hammering in the valve train. Typically street cars don't make good race cars and visa versa.
 
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