which tq converter for my 408 stroker?

[clinebarger]

While the FMX is a decent unit behind a stock & mildly modified Small Blocks, It will probably not live long behind a 408 stroker.

With all this money your spending on a 100% aftermarket engine....Why not round out the package with a Built AOD, 3000RPM Stall Lock-Up Converter & 3.90 or 4.10 Gears??

A 4R70W is even a better choice with the controllers now available, Opens up endless possibilities for Converter selection.

If you are after a mild set-up for cruising? A late Roller 351W block with Iron GT40 heads & a Mild Cam would have served you very well with a stock converter & 3.00:1 gears.
So will a MILD 408 Stroker....But your parts list does not reflect a mild build!
AFR heads are some of the best flowing heads out there, Also the most expensive, You can buy a whole Dart Pro 1 top end package for what your spending on just 2 AFR cylinder heads that you will never see the full potential of....Trick Flow is another choice for cheaper cylinder heads.

Sounds as if your engine builder is selling you something you don't need & probably don't want to get the most money he can out of you....I really hope that is not the case!

 

[marc1]

Originally Posted By: tomcat27
thanks. I'm doing some calculations and, if I am correct, my engine will turn at 2400rpm @ 60mph:

FMX 3rd gear ratio = 1:1
Rear end 3:1
tires are 25"

79" tire circumference divided from 5280' = 800 tire rotations per mile. considering the 3rd gear ratio and the rear end ratio, I believe that's 2400rpm @ 60 mph. obviously I dont remember, and I cant validate since the car is not running.

That being said, and per everyone's advice, I certainly DO NOT want to take the engine builder's advice of "at least 2500 stall".

we have not chosen a cam profile - that's how this conversation with the builder came up. we will talk Monday. thanks all! worst case, I stick with my stock converter and switch it out later if I'm not happy. I will push him to spec a cam along the lines of what was discussed here.

actually, since its my car, my engine, and my money, I can tell him to use the Lunati VooDoo.

why type of distributor gear with that? steel?


You can use the stock distributor gear with the hydraulic flat tappet camshaft. If you go roller you will possibly need a different gear depending on the material the roller is made from. The roller cam manufacturer you choose (if you go that way) can advise you on the distributor gear. There are lots of low cost options (polymer, steel etc.).

I am glad you have done the calculations with your gear and TD. You can see you need a camshaft with a lower RPM range and a stock or very moderate stall.

My cruising posse (all old iron 73 is the newest car, GTO's, Firebirds / TA's, Camaros, 442's etc.) consider me to be a bit of a Luddite as they have mostly gone roller (just me and my best friend from Jr. High are the hold outs he runs a solid flat tappet as well) where I have not. I have used hydraulic and solid flat tappets exclusively for 35 years and have never had an issue. I will unequivocally agree that you will make more power with a roller (either the new generation retro hydraulics or a traditional solid roller), decent reliability, no issues with wiping out lobes (unless the roller pin gives out or a link fails etc.) but I am not sold on the cost for a regular street driven car. Before the ZDDP crowd chimes in, I am talking about less than 350 lbs open which is fine for any street grind. I ran a Ram Air IV Judge with a Comp Solid for a decade (that cam smoked the stock 041 hydraulic... wow... totally improved the car!). The oil I used was all SF, SG, SH, SJ then SL / SM / SN starting when those were available off the shelf on sale oil. My LS6 Chevelle has had the General Competition ZL1 3959180 in it for almost 30 years (I am running a crate LS7 from the 80's, the born with LS6 is tucked away in a bag in the shop). I usually use Rotella T5 10w30 or Motomaster (up here that is Canadian Tire) 10w40 (that weight is gone now I think), I just happen to have 10w30 Redline in it now because I got that oil on a trade. I have adjusted the lash once on the Chevelle and that was only because I was tuning the duration (I decreased the lash to effect more duration and it runs a touch quieter not that I care about that) not because there was any wear. My pressure at full lift is (when fresh) about 310#. My ex-GTO no lash adjustment required either so don't fret about a solid flat tappet and the "you have to adjust them every year" crowd that is simply not true. If you are adjusting it excessively, then it is wearing and you need to look into that. Of course, if you pick a hydraulic flat tappet the adjustment is moot. Anyway just my $.02 on the roller thing in old street duty iron.

 

[Robenstein]

As some have mentioned, the FMX in stock form may not live long behind a strong engine unless you are very light footed. If I had that car and the money, I would be using a C6.

Also, the rear end ratio is on the tall side as mentioned. I would be looking more in the 3.25 or 3.50 range. With a C6 it would be a good around town combo.

 

[OVERKILL]

Originally Posted By: tomcat27
Originally Posted By: marc1
Originally Posted By: tomcat27

the rear end (it took some crawling to get to the tag and alot of cleaner) is a 9" 3.00 ratio.



Ok, good, simple. That is a highway ratio not a stop light to stop light ratio and that is fine. Choose a low RPM torque smooth camshaft. If you are going hydraulic flat tappet and with a 408 stroker look for less than 224 intake duration @ .050". A mechanical flat tappet you could get away with 230. If you are looking at a retro roller (expensive) then let me know as the above numbers do not apply.

I wouldn't go beyond stock. 1800 at the most. If this was a GM the L88 converter would be perfect for you and cheap.

FMX choices are limited. Hughes only has a 2500 stall. I do not know anything about Boss Hogs. If it were my car I would be using a regular stock converter and a Lunati VooDoo as below:

•Advertised Duration (Int/Exh): 262/268
•Duration @ .050 (Int/Exh): 219/227
•Gross Valve Lift (Int/Exh): .499/.522
•LSA/ICL: 112/108
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 1400-5800


what spec would change for a hydraulic roller cam?


It actually seems pretty similar to the TFS #1, which I ran in my 302. It worked well, came on at about 2,500RPM and pulled hard to the 6,250 limiter. Peak power happened around 5,900-6,000RPM IIRC.

Specs on the TFS #1 for comparison:

Basic Operating RPM Range: 2,000-5,500
Duration at 050 inch Lift: 221 int./225 exh.
Advertised Duration: 275 int./279 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.499 int./0.510 exh.
Lobe Separation (degrees): 112

I ran it with 1.7 ratio rockers for more lift. Mild idle, great driveability and it was relatively inexpensive.

Here's the cam:
http://www.trickflow.com/parts/tfs-51403001

Here are the lifters you'd need:

http://www.trickflow.com/parts/tfs-21400006

 

[Rhymingmechanic]

As someone said earlier, have a talk with your engine builder to make sure you're both understanding each other.

Here's what I'm seeing: Awhile back, you were going to rebuild, then stroke the factory engine. The block was cracked, so now it sounds like the plan is to build a race engine with the best parts in the wishbook. But above, you said you're just looking for a fun street cruiser with 3.00 gears.

I'm not a Ford guy, so consider that. But I just looked at crate engines on the Summit Racing site. They have an all iron 408, 345hp and 430ft-lb, for $3370. Would something like that fit your expectations and budget? There are wilder engines, but as hp goes up, so does the effective RPM range, so the gears and converter need to be matched. I know from experience that a big sloppy cam and highway gears are not satisfying.

 

[tomcat27]

I agree that the designer and I are on different pages. In talking to him he is replicating his own Ford build. I also agree that a crate engine would be cheaper and easier; but for personal reasons we are working with a builder - this is a father/son project and we originally intended to do the entire build ourselves (except for the machine work). The owner of the shop will let us assemble the engine with their oversight.

so... my current thought is to dial back on the cylinder heads and select a cam like the Voodoo that was suggested. Keep the torque curve low: somewhere in the 1800-5500 range is good, I believe.

should I use AFR 185's? Edelbrock RPM's? either of those should reduce the port volume and increase the velocity. right?

keep the stock converter. keep the FMX for now; if and when it breaks I will consider upgrading to a C6 and/or AOD. if I go the AOD route I would likely change the gearing to around 3.5

 

[OVERKILL]

Originally Posted By: tomcat27
I agree that the designer and I are on different pages. In talking to him he is replicating his own Ford build. I also agree that a crate engine would be cheaper and easier; but for personal reasons we are working with a builder - this is a father/son project and we originally intended to do the entire build ourselves (except for the machine work). The owner of the shop will let us assemble the engine with their oversight.

so... my current thought is to dial back on the cylinder heads and select a cam like the Voodoo that was suggested. Keep the torque curve low: somewhere in the 1800-5500 range is good, I believe.

should I use AFR 185's? Edelbrock RPM's? either of those should reduce the port volume and increase the velocity. right?

keep the stock converter. keep the FMX for now; if and when it breaks I will consider upgrading to a C6 and/or AOD. if I go the AOD route I would likely change the gearing to around 3.5


Skip the voodoo, it is flat tappet. We ran one in an SBC and it worked really well, but then so did the Comp roller stick we replaced it with when we were upgrading.

If you just want something that "works", go TrickFlow.

Heads:
http://www.trickflow.com/parts/tfs-51410004-m61

Head bolt kit:
http://www.trickflow.com/parts/tfs-92005

Entire top-end gasket set:
http://www.trickflow.com/parts/tfs-51400904

Camshaft:
http://www.trickflow.com/parts/tfs-51403001

Lifters:
http://www.trickflow.com/parts/tfs-21400006

Rockers:
http://www.trickflow.com/parts/tfs-51400510

Pushrod length checker:
http://www.trickflow.com/parts/tfs-9000

Adjustable timing set:
http://www.trickflow.com/parts/tfs-51478520

Use the intake you were already talking about.

 

[tomcat27]

Thanks!