what converter. 408

Posted By: Dodgenu

what converter. 408 - 04/22/14 12:43 AM

I just finished up a 12 to 1 408 stroker motor for my duster and it made a shade over 600 hp on the dyno and I'm wondering what converter everyone is running(904 trans 2.77 first gear)). Its 3000# on the track and it should run high 9s. I plan on shifting at 7000 and its a track only car.

Thanks in advance.

Posted By: Dan Halen

Re: what converter. 408 - 04/22/14 12:44 AM

If you post your dyno sheet, you'll get a better answer.

Posted By: Sport440

Re: what converter. 408 - 04/22/14 12:48 AM

Track only 5500 to 6200.

Posted By: Dodgenu

Re: what converter. 408 - 04/22/14 12:54 AM

Quote:

Track only 5500 to 6200.

The motor made max torque at 5600 so I figure stall should be some where between 5500 to 5800, But whos converter are you running?

Posted By: D-50

Re: what converter. 408 - 04/22/14 01:03 AM

Call Kenny Ford at PTC. He is also a mopar guy. I have a pretty good 60 ft. at 2950 lbs with his 8 in. convertor with a pump gas small block NA. Almost the same weight as yours. SEE Below.

Attached picture 8120093-CIMG0081.JPG

Posted By: Sport440

Re: what converter. 408 - 04/22/14 01:11 AM

Quote:

Quote:

Track only 5500 to 6200.

The motor made max torque at 5600 so I figure stall should be some where between 5500 to 5800, But whos converter are you running?

My first numbers were approximate based on your first post of info..

With this new info, that tightens things up abit. I agree with your 5500 to 5800. 5700 to 6000 should be the max window IMO

I run a Dynamic, but with the stall that you need Id go ATI Lots of other good ones though.

Posted By: pittsburghracer

Re: what converter. 408 - 04/22/14 01:26 AM

Don't even think about anything under a 5200 stall. Matts 360 picked up .50 in ET going from a 4000 to a 5200 and my 408 stalls at 5200 and is begging for more.

And we only shift at 6400rpm

Posted By: 79410aspenrt

Re: what converter. 408 - 04/22/14 01:32 AM

Talk to Lenny at Ultimate Convertor. He will build you a awsome Convertor. Great customer service and fact turn around time.

Posted By: B3422W5

Re: what converter. 408 - 04/22/14 02:03 AM

Kinda surprised it made peak torque that high, as assuming at only 12 to 1 compression I am guessing the cam is likely not much bigger than 270 ish at 50.

What heads and what cam if you don't mind posting that stuff.
My old 422 as an example ran a 273@ 50 roller and was 13.3 to 1 and 60 footed at 3350 on leafs in my signature. Convertor flashed at 5400 and shifted at 7000.
5800-6000 seems like a TON of convertor to me with a 4 inch arm. :think Unless you have really big heads.

Posted By: Eric

Re: what converter. 408 - 04/22/14 02:26 AM

Quote:

Talk to Lenny at Ultimate Convertor. He will build you a awesome Convertor. Great customer service and fact turn around time.

X's a butt load

Posted By: Streetwize

Re: what converter. 408 - 04/22/14 02:44 AM

Just talked to Lenny today about loosening my converter, Great guy, great customer care and service!

Posted By: Dodgenu

Re: what converter. 408 - 04/22/14 05:42 PM

Quote:

Kinda surprised it made peak torque that high, as assuming at only 12 to 1 compression I am guessing the cam is likely not much bigger than 270 ish at 50.

What heads and what cam if you don't mind posting that stuff.

The heads are edelbrocks that flow 290 @ .600 lift. The cam is an Ultradyne/Bullet NF, that is 272/280 duration at .050 635 lift solid flat tappet.
Thanks everyone for the suggestions. I will make some calls tomorrow.

Posted By: MR_P_BODY

Re: what converter. 408 - 04/22/14 05:52 PM

Quote:

Quote:

Track only 5500 to 6200.

The motor made max torque at 5600 so I figure stall should be some where between 5500 to 5800, But whos converter are you running?

Based on this.... and assuming your using a 904 or
a 727 I would run a 5800 stall... if you are gonna
run a glide it would be a bit higher

Posted By: Streetwize

Re: what converter. 408 - 04/22/14 09:03 PM

I've been PM'ing back & forth with John (Pittsburgracer) and he's been helping me out a ton helping me figure out my 60' and my stall options

I've always been primarily a stick racer for 30+ years so I've been trying to better understand the effect on stall and how you "target" your stall RPM to match the torque peak when you put the motor under load...and how it all relates to the Hook and weight you have to work with. It wasn't making sense to me why you would target your stall at 5300 RPM if your torque peak occurs between 4400 and 4800 (like a typical 12:1 408 with smallish heads and a 270-ish at .050 Flat tappet). but it's I suppose it's just like a clutch in that you're really targeting the RPM the load is going to try to pull the motor down to once it flashes to meet the load. I think I "get it" going dow nthe track it's just the getting off the line I'm vexed with....especially since I'm not trying to shock the tires very hard since I already have good initial hook for hte first 10-15 feet, my issure is I need to get to the fat part of the curve at that 10' mark and not further down the track like I have now. I'm not too far off, just far enough to be aggravated by it

I'm debating whether to loosen my 4000-4200 stall 9 1/2" (~$300) to 4800 (about the max I would dare flash the Rocky on the line. That would also help my issue with the vert pulling through the beams (overcoming the brakes) because a looser stall would be making less torque at the 3000-3200 2-Step setting.

The other option is a new Ultimate 8" on the tighter side (4800)...but that might not be in the budget right now....maybe I can pick up a good 8" core and Lenny can rebuild it for a little less all-in cost than an "all-new" unit.

maybe somebody can chime in about this. The "beauty of astroker is the torque "peak" tends to be broader and flatter than a shorter stroke motor of the same output. I would think that with a broader "sweet spot" (not much torque drop off on either side of the peak) it wouldn't necessarily be so critical to get the stall "dead on" the peak, you would have a bigger "target zone"? What am I not getting?

Thanks

BTW, not trying to hack, my motor is very similar so I think it's all related...

Posted By: B3422W5

Re: what converter. 408 - 04/23/14 05:06 AM

Max torque at 5600 seems a fair bit high to me with Eddie heads and 4 inch crank, in fact about 400-500 rpm higher than I would suspect, at least.
I dont care what that dyno said, it isn't right.

Posted By: onig

Re: what converter. 408 - 04/23/14 05:43 AM

Go to the link below.
MSHRED is selling a high quality converter that looks to be what you are looking for.

Re: 8" A1 race converter for 904

https://board.moparts.org/ubbthreads/show...rue#Post8102908

Quote:

A1 8" race converter for 904 for sale!
Went to 5500 rpm off the brake behind my small block. Used for one season only, regular fluid changes to keep everything clean, excellent condition. Only selling because I am going to a nitrous converter
$800

Posted By: Dodgenu

Re: what converter. 408 - 04/23/14 05:55 AM

I called ATI and they suggested an MRT treemaster 8 inch 5700 stall, so I ordered it and should have it by the end of next week.
I'll keep ya posted on the results.

Posted By: Ian

Re: what converter. 408 - 04/27/14 11:28 AM

Quote:

I called ATI and they suggested an MRT treemaster 8 inch 5700 stall, so I ordered it and should have it by the end of next week.
I'll keep ya posted on the results.

any updates mate

Posted By: Dodgenu

Re: what converter. 408 - 05/02/14 12:55 AM

Update.
I received my new converter and have installed it.After ATI got my build sheet they thought a 5400 stall would be better so thats what they shot for.Well guess what , it stalls to 5400 on the T brake. I did a little hole shot in front of my house and my neighbor said he saw 2 feet of air under the front tires.lol I'm gonna hit the track this weekend and see what it will do but it feels alot stronger than my 360 did and it ran 10.30s. Can't wait to hit the track. I will keep ya posted.

Posted By: pittsburghracer

Re: what converter. 408 - 05/02/14 12:58 AM

Quote:

Update.
I received my new converter and have installed it.After ATI got my build sheet they thought a 5400 stall would be better so thats what they shot for.Well guess what , it stalls to 5400 on the T brake. I did a little hole shot in front of my house and my neighbor said he saw 2 feet of air under the front tires.lol I'm gonna hit the track this weekend and see what it will do but it feels alot stronger than my 360 did and it ran 10.30s. Can't wait to hit the track. I will keep ya posted.

Good-luck. You should love the results.

Posted By: 77DragracerR/T

Re: what converter. 408 - 05/02/14 03:31 AM

Good luck at the track! I run a TCS 8" 5500 stall in my 904 behind my 408 and it works well and very consistent.

Posted By: Dodgenu

Re: what converter. 408 - 05/05/14 11:37 PM

I took my car to the Friday night test and tune race. The first pass I took an easy hit foot braking and ran 10.54 @ 90 mph lifting at about 900 foot . The second pass I left at 3000 on the T brake and my car really left hard, I still only shifted both gears at 6000 rpm and I lifted at about 1100 feet and I ran 9.91 @ 124. At half track I went 6.18 @ 111 with a 1.29 60 foot.. When I was driving up to the time slip booth I saw the track manager standing there and I knew I had ran in the 9s, I don't have a license for 9s nor is my car s cage certified so they told me to slow it down or go home so I went home.I feel I have a mid 9 sec pass( 9.50s-9.60s) in the car.I have now made an appoiment to get a physical and then get the car certed and make some license passes.

Posted By: B3422W5

Re: what converter. 408 - 05/06/14 01:25 AM

Fantastic job

That is the best running Eddie head motor I have ever seen or even heard about

Only 12 to 1 and 3000 pounds race weight that is flat out hauling the mail. Runs as good or better than most well sorted out Indy headed small block strokers.... Extremely impressive.
What body is the motor in, and who ported the heads and did the valve job?. What intake and headers?

Posted By: D-50

Re: what converter. 408 - 05/06/14 01:35 AM

Quote:

I took my car to the Friday night test and tune race. The first pass I took an easy hit foot braking and ran 10.54 @ 90 mph lifting at about 900 foot . The second pass I left at 3000 on the T brake and my car really left hard, I still only shifted both gears at 6000 rpm and I lifted at about 1100 feet and I ran 9.91 @ 124. At half track I went 6.18 @ 111 with a 1.29 60 foot.. When I was driving up to the time slip booth I saw the track manager standing there and I knew I had ran in the 9s, I don't have a license for 9s nor is my car s cage certified so they told me to slow it down or go home so I went home.I feel I have a mid 9 sec pass( 9.50s-9.60s) in the car.I have now made an appoiment to get a physical and then get the car certed and make some license passes.

By your 6.18 1/8 et. on Wallace calculators said you would run 9.79 1/4 and your 1/8 mph says 9.70 et.

Posted By: B3422W5

Re: what converter. 408 - 05/06/14 01:50 AM

Quote:

Quote:

I took my car to the Friday night test and tune race. The first pass I took an easy hit foot braking and ran 10.54 @ 90 mph lifting at about 900 foot . The second pass I left at 3000 on the T brake and my car really left hard, I still only shifted both gears at 6000 rpm and I lifted at about 1100 feet and I ran 9.91 @ 124. At half track I went 6.18 @ 111 with a 1.29 60 foot.. When I was driving up to the time slip booth I saw the track manager standing there and I knew I had ran in the 9s, I don't have a license for 9s nor is my car s cage certified so they told me to slow it down or go home so I went home.I feel I have a mid 9 sec pass( 9.50s-9.60s) in the car.I have now made an appoiment to get a physical and then get the car certed and make some license passes.

By your 6.18 1/8 et. on Wallace calculators said you would run 9.79 1/4 and your 1/8 mph says 9.70 et.

He also said he shifted it at 6k just shaking it out. And it was a first outing. It might well easily run 50's or 60's.
That said, any Eddie head stroker motor I have ever seen always lays down on the back half of the track with a 4 inch crank. The port volume just isn't there.

Posted By: D-50

Re: what converter. 408 - 05/06/14 02:02 AM

Quote:

I took my car to the Friday night test and tune race. The first pass I took an easy hit foot braking and ran 10.54 @ 90 mph lifting at about 900 foot . The second pass I left at 3000 on the T brake and my car really left hard, I still only shifted both gears at 6000 rpm and I lifted at about 1100 feet and I ran 9.91 @ 124. At half track I went 6.18 @ 111 with a 1.29 60 foot.. When I was driving up to the time slip booth I saw the track manager standing there and I knew I had ran in the 9s, I don't have a license for 9s nor is my car s cage certified so they told me to slow it down or go home so I went home.I feel I have a mid 9 sec pass( 9.50s-9.60s) in the car.I have now made an appoiment to get a physical and then get the car certed and make some license passes.

What gear ratio and how tall are your tires?

Posted By: Dodgenu

Re: what converter. 408 - 05/06/14 05:33 PM

My dad built the motor and ported the heads. He is a retired mechanical engineer and has been building and racing mopars for 35 years. He spent alot of time on this build and one of the things he did was remove( knife edged counter weights) a bunch of weight off the forged scat crank (around 11 lbs). We run 4.30 gears in the dana with a 29.5-11.5 Phoenix tire. Plan on testing again in a couple weeks and I will keep ya posted.