Lets Build a 408 MOPAR!

[tchapps88]

hypothetical kind of build- rules follow as this

max 410 ci
block and intake must be ones readily available to the public, block must be cast iron
heads must be brodix aluminum spec heads
holley 4150hp carb no cfm restriction
must use msd 6al type box with 7500 limiter chip
roller cam/ rockers permitted
can use dry sump with 4 stages max

rules on the heads-
Only approved spec Brodix heads are allowed. No removing, relocating, grinding, polishing or
defacing of any letter or number cast into the cylinder head ports is allowed.
2. Only the following part numbers are approved for use.
a. Chevrolet – SPCH WISSOTA
b. Fort – SPFO WISSOTA
c. Mopar – SPMO WISSOTA
3. Valve guides must remain in original angle and spacing as manufactured. Valve guide may not be tapered,
thinned or shortened in any way.
4. No welding or adding material is allowed.
5. Combustion chamber may be ground for clearance and polished.
6. Intake bowl may be blended and polished from the valve seats to the edge of the letter “C” in the word
“SPEC” on the roof and floor of the intake port. The side of the intake may be blended and polished from
the valve seat to the same point as the roof and floor. No grinding or polishing along the side walls where
the spec logo is cast.
7. Exhaust seats may be blended into the exhaust bowl and port may be polished as long as the word “SPEC” is
in the roof of the exhaust port is not touched and the exhaust port exit at the header flange remains in the
original as cast location, size and shape.
8. Cylinder heads may be machined for push rod clearance.
9. No grinding or polishing of any kind, other than stated above, is allowed

here is what the chevy, ford, and mopar flow charts are from brodix-
Part Number Valve Size .200 .300 .400 .500 .600 .650 .700
SP CH 2.080 Intake 121 176 223 249 261 265 269
1.600 Exhaust 92 134 158 172 179 182 182
SP FO 2.080 Intake 120 180 224 255 267 268 270
1.600 Exhaust 103 130 159 179 191 198 202
SP MO 2.080 Intake 129 180 221 249 263 267 269
1.600 Exhaust 119 160 182 190 195 196 198

link to the heads- https://brodix.com/heads-2/ford-mopar/spec-series

this engine is for a pro 2 short course off road truck, fords are the main choice for most guys, no one runs a mopar, i get that aftermarket blocks are almost non existent but looking at the flow chart, the mopar intakes run neck and neck with the fords and outflow them on the exhaust, finding an old r2 or r3 340 block would be nice but most rotating kits would make them a 416, so kinda forces you into a 360 block with perhaps a main girdle for strength and use a victor 340 intake, maybe something from indy? like to hear what you guys would do

[PRH]

Step one......Actually procure a block and have it thoroughly inspected and make sure it’s a viable candidate before going any farther.

The rest is pretty basic.

[Walter R. Malik]

What RPM range are you intending to run and how heavy is the vehicle it will be in ...?

Put together your own kit ... I would start with a .040" over 340 race block, (preferably one which can accept 48 degree lifter bores from Ritter), and a 3.910" stroke crankshaft having a small Chevrolet crank pin using a 6.200" length rod or a 6.300" custom rod.

[ou812]

Yes, Ritter block, 48° won't work with those heads, unless you do a bunch of machine work (might not be legal).
How much power are the other brands making? No other deets...? compression? fuel? headers??????????

The engine can be made to keep up with the other brands IMO, but you'll spend more than them doing it!

[Krooser]

Very close to the Wissota spec engine except for cubes....the 362 engines are around 650 HP.

As far as cost...the heads are the same. Custom cam is the same. Pistons too. Chevy rods are the same. Or use a set of ex NASCAR Pankl rods that you can buy on fleabay for $100.00. Really most parts are close in cost
..a good 360 two bolt block will hold up to about 700 HP.

[ProPower engines]

What is allowed for oiling system. Stock wet sump or a dry sump system?

[Walter R. Malik]

Yes, Ritter block, 48° won't work with those heads, unless you do a bunch of machine work (might not be legal).
How much power are the other brands making? No other deets...? compression? fuel? headers??????????

The engine can be made to keep up with the other brands IMO, but you'll spend more than them doing it!

The "Ritter" block will certainly work with regular small block Mopar heads; the extra 8 head bolt holes simply are not used and the cylinder head pushrod holes need to be aligned is all ... been there.

If it is all done right the first time there will be no need to ever re-do it; especially with a dry sump oil system.
Although ... you can definitely build a "run of the mill" type engine and you will merely get "run of the mill" results.

[PRH]

I’m pretty sure the issue Brian is referring to is the fact that the 48* lifter bank angle often doesn’t play well with heads designed for a 59* lifter bank angle.

[ClassAct]

I’m pretty sure the issue Brian is referring to is the fact that the 48* lifter bank angle often doesn’t play well with heads designed for a 59* lifter bank angle.

I thought Ritter also made a 59* LBA block?

[Walter R. Malik]

I’m pretty sure the issue Brian is referring to is the fact that the 48* lifter bank angle often doesn’t play well with heads designed for a 59* lifter bank angle.

The angle of the cylinder head pushrod holes is the only drawback however, the slightly relocated holes can be smaller as the pushrod does not move "sideways" as much.
Having much better valve train dynamics is well worth the effort of moving, (re-angling), the pushrod holes.

EDIT: Personally, I'd build a big bore, (4.180"), Dart block Ford.

[tchapps88]

What RPM range are you intending to run and how heavy is the vehicle it will be in ...?

Put together your own kit ... I would start with a .040" over 340 race block, (preferably one which can accept 48 degree lifter bores from Ritter), and a 3.910" stroke crankshaft having a small Chevrolet crank pin using a 6.200" length rod or a 6.300" custom rod.

minimum weight is 4000 pounds, rpm is limited to a 7,500 rpm chip

[Krooser]

I agree with using the Ritter block if the budget allows. Of course simply having the block does not guarantee it will be ready to assemble... no different than any performance block.

[Walter R. Malik]

What RPM range are you intending to run and how heavy is the vehicle it will be in ...?

Put together your own kit ... I would start with a .040" over 340 race block, (preferably one which can accept 48 degree lifter bores from Ritter), and a 3.910" stroke crankshaft having a small Chevrolet crank pin using a 6.200" length rod or a 6.300" custom rod.

minimum weight is 4000 pounds, rpm is limited to a 7,500 rpm chip

Given the 340 cranks which are readily available in the marketplace,
I would use a 3.79" Molnar crank with someone's 6.250" or 6.300" rod and that Ritter block using a bigger 4.145" bore.
Reading your rules it says that " combustion chamber may be ground for clearance and polished" to that bore size.
"Cylinder heads may be machined for pushrod clearance" is also there.

If using a factory 340 block ... then the offset ground 3.910" stroke would be most beneficial with that 4.080" bore.

Nothing you do with a REAL RACE small block Mopar will be inexpensive; if most inexpensive is the route you wish to take and be somewhat competitive then use a 9.300" Chevrolet DART block and go from there.

[ou812]

I’m pretty sure the issue Brian is referring to is the fact that the 48* lifter bank angle often doesn’t play well with heads designed for a 59* lifter bank angle.

The angle of the cylinder head pushrod holes is the only drawback however, the slightly relocated holes can be smaller as the pushrod does not move "sideways" as much.
Having much better valve train dynamics is well worth the effort of moving, (re-angling), the pushrod holes.

EDIT: Personally, I'd build a big bore, (4.180"), Dart block Ford.

Have you ever relocated pushrod holes from 59° to 48°? It's more than just slight...

[ClassAct]

I’m pretty sure the issue Brian is referring to is the fact that the 48* lifter bank angle often doesn’t play well with heads designed for a 59* lifter bank angle.

The angle of the cylinder head pushrod holes is the only drawback however, the slightly relocated holes can be smaller as the pushrod does not move "sideways" as much.
Having much better valve train dynamics is well worth the effort of moving, (re-angling), the pushrod holes.

EDIT: Personally, I'd build a big bore, (4.180"), Dart block Ford.

Have you ever relocated pushrod holes from 59° to 48°? It's more than just slight...


Yep...it's a mess and not really worth it in the end.

11* LBA change is HUGE and it also moved the bottom of the lifter away from the cylinder side of the block.