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Muscle Motors Racing - Mopar Stroker Kits / Crate Engines And More!

The Little Engine That Could!

Muscle Mike of MMR

I get this call about a year ago from a racer/friend of mine. Tracy Sons is an accomplished big buck bracket racer that uses Mopar power. Tracy asked me “if there was a wedge head that would run significantly faster than his current 440-1 engine.” I wanted to know how much faster? Tracy asked if we could build him something that would run 4.60s’ in the 1/8, 7.40 in the 1/4 (most big dollar bracket races are run on 1/8 mile) in his 1875 lb dragster. Tracy continued that: it must be a low RPM, low maintenance, and run on relatively cheap race gas (no Gucci $12 a gal oxygenated fuel). I said sure, no sweat!

I would build this combo with B1-PSO heads. You may ask (because Tracy did) “What are B1-PSO heads?” PSO stands for “Pro Stock Option” this was the very first head that Wayne County used back in the late 80’s when Darryl Alderman went NHRA Pro Stock racing. Externally the head looks exactly the same as a traditional B1 head. The intake and exhaust port openings are in the stock location. The difference is that the ports are raised within the head. This gives the head more short side radius and the roof is also higher in the casting. This requires a longer valve and special drilling of rocker stand location. What this means is you can get A LOT more airflow thru the head. Typical B1 heads flow anywhere from 400-420 CFM. The PSO’s will flow over 475 CFM with our CNC porting!!! Tracy already had an aluminum wedge block, headers, B1 intake, etc so that is why we went PSO heads instead of a Predator. Predators will still make the most power but for low RPM/low maintenance, I feel the PSO is a better choice.

I decided that Tracy’s 4.500 bore block needed new life so I bored and honed it out to 4.530, that with a 4.500 crank makes 580” engine. Next the heads 2.400, 1.81 valve combo with our CNC porting gives us a Killer cylinder head. NOTE: PSO head come with head bolt, intake and exhaust bolt holes and that is IT! We had to drill the head for valve guide angle and location, valve seat location, rocker stand location, etc, etc. THESE ARE NOT FOR A NOVICE ENGINE BUILDER. Anyway, castings were now machined, ported and ready to assemble. I then drilled the head for typical B1 oil drain backs (required). I used stainless steel valves (yes I said Stainless) with 11/32 stems. I believe there is no need for titanium when the RPM’s are kept so low. Since I was location the rockers where ever I wanted I made sure we had a valve long enough to have 2.100 installed height spring. This will allow a “big cam” at a later date if we want to make a change. I choose a cam to keep the peak power below 7000 RPM and peak torque below 5500 RPM’s. A different cam with more lift, duration and lobe separation would make more power but it would also need compression and RPM, two big No No’s on the project. What we ended up with was a single 4bbl engine that runs great on 110 octane fuel, and makes peak power of 1004 HP @ 6500 and peak torque of 850 Ft/lbs @ 5300!! All of this with 31 degrees timing!

Read more: The Little Engine That Could!


400 Kits

400/451”: 3.75 stroke x 6.76 rod, 4.375 bore 1.320 CH piston.

One of the original stroker kits for big block Mopars. These kits are noting more than a 440 built with a really light piston. 3.75 x 6.76 (440 stroke and rod) but because the block is 3/4”shorter, the piston is ¾” shorter and literally ½ the weight. We use a new 4340 crank an rods with your choice of forged pistons. Rings, bearings and balancing included.

Only: $1999

400/470”: 3.91 stroke x 6.700 rod, 4.375 bore 1.320 CH piston.

This is one of those kits that works better than it should. When using stock port window cylinder heads (factory, Edelrock RPM, Stage VI) this is the PERFECT combination. Good amout of cubes, super lite weight rotating assembly, great rod ratio, just a dynamite combo.

Only: $1999

400/511”: 4.25 stroke x 6.535 rod, 4.375 bore 1.320 CH piston

My personal favorite combo for competition. These kits work really well with bigger port heads such as 440-1’s or B1’s. In a 400 block I don’t build anything bigger because there just isn’t any point in a stock block! This combo has a piston with a 1.320 compression height. What that all means is that it stops the piston at zero deck on an unmachined block. We charge an additional $100 to mill to tops of the pistons down (before balancing) to make sure you don’t end up with a positive deck piston or not enough piston to head clearance.

Only: $2099


All you ever wanted to know about Predator heads!

Muscle Mike of MMRWhat is a Predator head?

A Predator head is a symmetrical port cylinder head that is designed to fit on a 4.800 bore spacing block. It features an oval intake port that is deigned for maximum airflow with minimal cross sectional area. Port volume starts @ just over 420 cc’s and can get as big a 480 cc’s max ported. It uses valves that are 6.800” long (almost 2” loner than a stock 440 valve) and has a 2.400 intake and 1.850 exhaust valve. The intake and exhaust valves are both canted. What this means is the valves open on a compound angle. As the valve lift increases the valve actually moves towards the centerline of the bore. This increases the unshrouding of the valve as valve lift increases (more lift/more flow= more power!) Out of the box, with the correct valve job and blending of the seat the heads will flow over 485 cfm on a 4.500 bore. Properly ported the heads are capably of flowing over 530. Combustion chambers come CNC ‘ed and will start life around 85 cc.

The head can be ordered with a Wedge or Hemi head bolt pattern. This allows for “off the shelf” availability of many different choices for gasket thickness and design. The Hemi or Wedge bolt pattern availability allows the user to use a preexisting short block (B1, Indy and Hemi) and this way you can upgrade your engine program to a better flowing cylinder head without have to buy everything from scratch.

Read more: All you ever wanted to know about Predator heads!


The Little Engine That Could!

Kit ImageFor years, the 383 has been the red headed step child of Big Block Mopar’s. I’m not really sure how that came to be. Everyone I know has a story or a fond memory about a 383 “back in the day”. Some tale of a high winding, indescribable, take all comers, that always came back for more. An engine that would not die no matter how hard you abused it. Now like all stories, the reality of what is remembered and what really happened are usually two different things. That being said, 383’s were very resistant to abuse from the factory. The short stroke (3.375) is less than a 1/16” of and inch longer than a 340 so 383’s loved RPM. That coupled with fact that the connecting rods were just under a ½’ shorter than 440 rods made them very compact and strong (read: durable). The short stroke, short (strong rod) made 383’s high winding animals that would take a lot of abuse.

Fast forward 20 years. When everyone started rebuilding big blocks, the natural choice was a 440. Parts cost the same and why not take the extra 57 cubic inches. Then the 400 block was the hot ticket. The short deck height meant shorter/lighter pistons and it had the biggest bore of any Mopar big block. The 400 and 383 are the same except for the 400’s bore is .090 BIGGER so it was always chosen first.

Fast forward another 20 years, the new millennium. After market parts are very plentiful. There is a whole host of choices for heads, cranks, rods, intakes, etc. This means that making power is easier today than it has ever been before. A stroker kit and a set of aftermarket aluminum heads and you can make 550-600 Hp all day long!

Kit ImageNow that it is 2009 that means that there hasn’t been a big block produced by Mopar in 31 years. Junk yards are practically a thing of the past. Core 440 & 400 engines are very difficult to find and usually expensive to buy. Now most Mopar guys I know usually have 1 (or more) 383 blocks laying around under a bench or out in a shed. Given the amount of aftermarket components available, now even the lowly, long forgotten, redheaded step child 383 can be a tire frying, fire breathing Monster Mopar!

Part or the reason 383’s we not the first choice for performance rebuilds is the bore size. At 4.250 it is significantly smaller than either the 440 or the 400. The smaller the bore the more the valves are shrouded. The more the valves are shrouded the less air the heads will flow. Now if we are talking an all out, race only application, FIND a 440 or 400 block. If you are building a high horsepower street car(something to take the family to car shows, down to the local drive in, or a little stop light to stop light action) the 383 will easily fit the bill. A balanced stroker kit, new cam and intake with bowl ported stock heads 475HP-525HP is easily attainable. With an aftermarket head, let’s say a Edelbrock Performer RPM 550-600HP is not a problem. Can you make more with a bigger bore 400, sure. The point is you can make a TON of power, more than you will ever need on the street, with a core block that is probably out in your garage.

Because of the availability of the 383 block we now feature 2 stroker kits exclusively for the 383. A 450” kit: Brand new 4340, heat treated cranks w/3.90 stroke, 4340 H-bean connecting rods, Forged aluminum pump gas Ross pistons, rings, bearing, balanced and ready to go. We also have a similar kit with a 4.25 stroke crank that makes between 489-496” depending on bore size.

Either way you choose, (450” or the 496”) a 383 based stroker engine can be a real sleeper that makes tons of power and can be done cost effectively.


Just Completed!

Tony Raffin’s 70 Cuda. Right now the finishing detail touches are being completed. Nitrous supply lines, updated Racepak sensors and a few plumbing details. After that a little bit of lettering and then a day or two of track rental to get everything dialed in and then into competition. When that will be depends on weather. Tony needs some seat time and a ½  dozen shake down runs before we put him and the new car into Top Sportsman & Q 16 racing


Just Completed :: Image 1 Just Completed :: Image 2

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