408 build

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Solid_Brass

Solid_Brass

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360 Magnum block is off at my machinist, hopefully get everything back at the end of the month. The end use for this engine is a street cruiser, not a track car. It will be going in my D200, but will eventually end up in my 70 duster. Rear end is Ford 8.8 with limited slip and 3.73 gears. Transmission is a 46Rh. I havn't decided on a torque converter yet. I'm not building for a specific HP number, just hoping in the mid 400's. It's getting a Scat 408 stroker rotating assembly (cast crank), Icon Forged -20.5cc dish pistons, and Scat I-beam rods. Heads will be Speedmaster 45cc (LA heads). Buying bare heads so I can have my machinist install new valve seats and guides, and I can port match exhaust in intake. Compression should be around 10 to 1 depending on if my machinist needed to deck the block any to square it. I wanted it to be 10 to 10.5 to 1 so I can use pump gas. It will be getting Holley Sniper 2 efi.

I'm trying to figure out what cam, rockers, lifters and intake to go with. I will need pushrod oiling so my lifters will need that feature, and thinking of 1.6 ratio. I would like to stay hydraulic roller. Intake I was thinking an Air Gap. For the cam, I would like the engine to have a little lobe to it, but something that will drive nicely if I take a weekend roadtrip to the coast. The only part of this engine build I already have is the block, and an MSD ignition system.

Nothing set in stone yet other than it's going to be a 408 stroker. I should hear back next week what it gets bored to so I can order the rotating assembly. As far as parts budget, 6k-ish. I don't really have a number i'm sticking to as I will buy/build as I can afford. I will be building the engine myself and this will be my first mopar engine. I am a Tool & Die machinist by day. I did buy the apropriate mopar engine books and have been reading them.

I apreciate any help and guidence

The rides:
166401604_10225446019322011_7081759517724343984_n.jpg

765c8a7e-b8ac-43b8-890e-686f0dece826.jpg
 
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I think your going to need rockers that oil through the lifter/pushrods too or modify the heads for external oil to them.
 
I’m curious you’re going to assemble the engine yourself. I have everything to assemble a stroker but thinking it’s best to have the machine shop assemble it. I’m worried about the balancing part of it being all new parts.
 
I'm going to do the assembly myself. While it is my first Mopar engine, I feel comfortable doing it. I like doing that kind of stuff, my happy place. I'm sure I'm gonna stumble my way through it, probably ruin a set of cam bearings. My machine shop is balancing my rotating assembly. So that should be all good.
 
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Out of curiosity, why buy Speedmaster heads then have the seats and guides replaced when you can buy an AFR or ProMaxx head with better parts already installed? You would end up with a better casting at a lower final cost.
 
Earlie A said:
Out of curiosity, why buy Speedmaster heads then have the seats and guides replaced when you can buy an AFR or ProMaxx head with better parts already installed? You would end up with a better casting at a lower final cost.
Click to expand...
I was going to say exactly this.
 
I hadn't come across Promaxx heads yet, will have to read about them. Pretty sure SM and AFR come from the same China foundry. I assume AFR machines them in house. That might be a better option, save a few $$. I will have to do some more reading. I haven't 100% decided on heads. @Icetech I have been following your build for a while, and I really appreciate the time you take to document everything (good and bad).
 
Solid_Brass said:
I hadn't come across Promaxx heads yet, will have to read about them. Pretty sure SM and AFR come from the same China foundry. I assume AFR machines them in house. That might be a better option, save a few $$. I will have to do some more reading. I haven't 100% decided on heads. @Icetech I have been following your build for a while, and I really appreciate the time you take to document everything (good and bad).
Click to expand...

If you can swing AFR over SM... do it... doesn't matter on the foundry, it's the company that finishes them and the parts used that matter.. AFR never really makes bad stuff and will give you a better product.. i have owned AFR heads and zero complaints right out of the box.
 
And not to derail.. but just looked... complete afrs are $795 each complete.. that's insane (as in good)
 
Look what @RAMM just did with a set of AFRs. Post 161 below

R

Thread '360 Magnum Build SFS (S-crounging F-or S-craps)'

So I figured I wasn't getting any younger and waiting for this world to normalize probably isn't going to happen for awhile, decided to go ahead and try and build a decent small block based on a 5.9 core I had lying in wait. This IS destined for my 83 D-150 Shorty and it IS going to be completed by spring/summer of 2023 one way or the other. The plan is to spend as much time with my younger ones and keep my daughter (who is right into this stuff) away from the boys. I gotta say its been interesting sourcing even the most basic of parts like camshafts, pistons, bearings and even certain...
 
You will need a front sump pan to put the motor in the D200, so you'll have to do some head scratching on that. As far as I know, there was never an LA 360 pan made in front sump configuration. A 273/318/340 pan will not work on a Magnum motor. Maybe someone who has tried a mid (car) sump pan in one of those trucks will chime in. It would be great if that would work in the truck, because you would need to change it when the motor goes to the Duster.
 
JDMopar said:
You will need a front sump pan to put the motor in the D200, so you'll have to do some head scratching on that. As far as I know, there was never an LA 360 pan made in front sump configuration. A 273/318/340 pan will not work on a Magnum motor. Maybe someone who has tried a mid (car) sump pan in one of those trucks will chime in. It would be great if that would work in the truck, because you would need to change it when the motor goes to the Duster.
Click to expand...

didn't know that.. i thought all trucks were rear...

got a welder and some metal? a kframe isn't special and can be made to work with anything :)
 
The 60's and 70-71 D series had front sumps in both small block and big block trucks. It was because of the straight axle front end. I used to have a super nice D200 big block truck that came from CA and was rust free. The oil pan was a mile above the axle, so I always wondered if a car pan would work if that's all you had. My truck was a 2WD, and it appears the OP's truck is too.
 
The price of the AFR heads really is good IMO. Didn't realize there wasn't a front sump 360 pan. I will just cut the bottom out the pan I have and fab my own. I was looking at the Milodon pans and wasn't impressed with the quality of welding for the price. Then I can add more capacity too.
 
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Solid_Brass said:
360 Magnum block is off at my machinist, hopefully get everything back at the end of the month. The end use for this engine is a street cruiser, not a track car. It will be going in my D200, but will eventually end up in my 70 duster. Rear end is Ford 8.8 with limited slip and 3.73 gears. Transmission is a 46Rh. I havn't decided on a torque converter yet. I'm not building for a specific HP number, just hoping in the mid 400's. It's getting a Scat 408 stroker rotating assembly (cast crank), Icon Forged -20.5cc dish pistons, and Scat I-beam rods. Heads will be Speedmaster 45cc (LA heads). Buying bare heads so I can have my machinist install new valve seats and guides, and I can port match exhaust in intake. Compression should be around 10 to 1 depending on if my machinist needed to deck the block any to square it. I wanted it to be 10 to 10.5 to 1 so I can use pump gas. It will be getting Holley Sniper 2 efi.

I'm trying to figure out what cam, rockers, lifters and intake to go with. I will need pushrod oiling so my lifters will need that feature, and thinking of 1.6 ratio. I would like to stay hydraulic roller. Intake I was thinking an Air Gap. For the cam, I would like the engine to have a little lobe to it, but something that will drive nicely if I take a weekend roadtrip to the coast. The only part of this engine build I already have is the block, and an MSD ignition system.

Nothing set in stone yet other than it's going to be a 408 stroker. I should hear back next week what it gets bored to so I can order the rotating assembly. As far as parts budget, 6k-ish. I don't really have a number i'm sticking to as I will buy/build as I can afford. I will be building the engine myself and this will be my first mopar engine. I am a Tool & Die machinist by day. I did buy the apropriate mopar engine books and have been reading them.

I apreciate any help and guidence
Click to expand...
This will be a nice build. I built a 408 magnum stroker in the winter of 2025. I used the same reciprocating assembly as you, came in at 10.4:1 with TF heads. The Eddy Air Gap intake would be about the perfect intake for this engine. You didn't mention headers, but I assume you'll be installing them too.
The magnum is a hyd roller and there are dozens of cam choices. I went with a 238/242 @.050", .576/.587 lift with 1.6 rockers. It's on a 110° LSA so the engine has good idle manners. My Dart has manual brakes, so idle vacuum wasn't an issue. About half way through my build I discovered B3 Racing Engines. Their owner, Mike Beachel, has to be one of the best Mopar vendors out there. I talked to him several times over the phone and met him at Carlisle. I recommend giving him a call and he will set you up with the best cam and valve train for your application.
The build was also my first. The How To books are helpful. Another great resource is on this site, under the Articles forum. There's a 20+ part rebuild series by krazykuda that I referenced almost daily.
BTW, with the parts you're assembling, you're already on your way to achieving 400 hp. Depending upon the cam and head selection, you can hit 450 without much effort. I'm going to enjoy watching your progress.
 
Solid_Brass said:
I hadn't come across Promaxx heads yet, will have to read about them. Pretty sure SM and AFR come from the same China foundry. I assume AFR machines them in house. That might be a better option, save a few $$. I will have to do some more reading. I haven't 100% decided on heads. @Icetech I have been following your build for a while, and I really appreciate the time you take to document everything (good and bad).
Click to expand...
Don’t be to sure where they are cast. It doesn’t matter. The end product matters. MoPars W5 head was an American casting that sucked balls. They took Chrysler for a ride to know where while emptying their wallets.

The Chinese casting are shipped to ProMaxx in Alabama (IIRC) Where they do the finishing work.

I have a set, they are very good. Also lots of room to go a good bit further. But by that time you do that it’ll cost more than the Trick Flow heads.

The Trick Flow heads outflow the ProMaxx heads up top by 20cfm. They are a sweet casting and the work done on both heads are very good.

What ever head you go with and I only suggest these two heads to choose from, just lift the valve as much as you can to take advantage of the heads flow capability. Otherwise your just wasting money.
 
JDMopar said:
The 60's and 70-71 D series had front sumps in both small block and big block trucks. It was because of the straight axle front end. I used to have a super nice D200 big block truck that came from CA and was rust free. The oil pan was a mile above the axle, so I always wondered if a car pan would work if that's all you had. My truck was a 2WD, and it appears the OP's truck is too.
Click to expand...

I am using a rear sump 318 truck pan on my 414" 340 in my'67 Sweptline. Lots of miles on rough roads, no problem. Axle is way away, steering arm is closer, but never will hit. Skip the first minute to see.

 

Mopar Sam said:
I am using a rear sump 318 truck pan on my 414" 340 in my'67 Sweptline. Lots of miles on rough roads, no problem. Axle is way away, steering arm is closer, but never will hit. Skip the first minute to see.
Click to expand...

That is good to hear, thanks for the info. I do have the origional Magnum pan. Is your front end lowered at all?
 
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