Boss 331
 

Has anyone tried the Boss based 331 cu. in. crate motor from Ford Motorsports? I'd be interested in your input.
I have not heard much about them and I was thinking that I need one in my ERA Fia.

It’s just a name they slapped on their r-block, with a few extra bells and whistles, for marketing purposes and has nothing to do with the original boss combination, canted valve head in particular. I have no experience with their new Windsor head 331 crate motor.

John ;)

I have the FR BOSS 302 block for my build , large amounts of iron everywhere you look.

I have not reviewed their crate offering in the 331. My plan is a 331 based on the eagle stroker kit.

Note: you will need the S331 head gaskets and the FE ARP head stud kit..

Send me a PM if you have questions.

Steve

I have the new BOSS 302 block in m racecar, it is a 331 stroker also...... Block is VERY meaty and everything on it is heavy duty and machined, a true work of art.................but,beware, they give you very little info when you buy the block and calling the Ford Motorsports Tech Line is a joke!!!!!!!!!!!!! They give you absolutley NO techincal advise on head bolts/studs, head gasket or anything else you ask them.....
And they ARE having "Some Issue's" with the 4.125 bored blocks, that's according to what the tech guy let slip..........

David

think i read somewhere the cylinders are little shorter, so beware if you're going max stroke.

The cylinders are not as "deep" as on a standard factory block....for up to 3.4 stroke, there is plenty of clearance....
On my original engine, I was using a factory block and had to notch the bottom of the cylinders for rod bolt clearance on a 331, 3.25 stroke......

Cylinders are quite a bit thicker than a factory block, you can go to 4.125 bore with this block.......

David

So what is the recommended head gaskets, studs/bolts, etc? I also believe the screw in soft plugs are sold separately from the block.

Roush Performance is about to release a new version of the CROSS BOSS engine. I have a picture of it in my gallery.

http://www.clubcobra.com/photopost/s...3&ppuser=26121

i don't think the issue is with crankshaft clearance, it is the piston dropping out the bottom of the cylinder distance.

Screw-in plugs come with the block.....not only are the freeze plugs screw-in, but all the oil galley plugs are the same and all screw-in plugs have O-rings on them and correspond to the machined block for sealing........

David

I've looked at mine from the bottom up when assembling the short block and while it does look like the bottom of the pistons stick out the bottom of the cylinders a lot, it is actually very little difference from a factory block......
No way the piston can "drop out" the bottom of the block while still connected to the rods and crank.......

David

There is NO recommended head gasket/stud kit from Ford, they refuse to tell you what to use!!!!!!!!!!!!!!!!!!

I used some 351-C head gaskets (Fel-Pro) and ARP head bolts, but I'm going with head studs now.......the block is basically a Cleveland block and you may or may not have to drill the steam holes in your heads if you'er using Windsor heads, just depends on which head you use.....most need the steam holes drilled in them!!!!!!!!!!!

Standard head gasket DO NOT cover all the water jackets, as this block had 8 extra water jacket holes in it, it takes a Cleveland head gasket to cover them, I found out the expensive way, cause once you open a sealed pack of Fel-Pro head gaskets, they are yours and Ford Tech refuses to tell you all this........................I now have two sets of unsued Fel-Pro head gaskets!!!!!!!!!!!! Thanks to the Ford Tech folks...........

Cam bearing are another thing, depends on the cam as to what cam bearing you have to order and they are not cheap......

If I had to do it all over again, I'd go with the Dart block.......it's a little more expensive (about $800.00 worth), but all your Windsor stuff will bolt on, cause it's a Windsor block...........saw one at the machine shop I use and it's every bit as good as the BOSS 302 block!!!!!!!!!!!!!!!!!!!!!!!!!!

David

I would recommend going with a Dart block as from all I have read I believe it to be a superior block. You can build a great stroker motor - with the 4.125 bored Dart blocks.

Rick;

When you order the BOSS 302 block, you have to specify which bore you want,4.0 or 4.125.........most all the aftermarket or non-OEM blocks are built to go to 4.125 bore....

The Dart and Boss block have almost all the same upgrades and features, cept the Dart block is a Windsor block, whereas the BOSS block is based on a Cleveland block.....the only advantage I can see with the BOSS block is the oiling system.... It has been upgraded and is very different from the factory blocks, you can use either wet sump or dry sump with block, it's basically a NASCAR block.......

I also think the screw-in freeze plugs as well as the oil galley plugs are also a plus, although I've never had a problem with the standard freeze plugs or oil galley plugs.........

David

I feel that the Dart is the best block going for the money. They are about the same money and the Dart will go a bigger bore. You need as much cylinder length as possible on the 302 blocks with stroker cranks because of the short cylinder pulling the piston out at the bottom and rocking the piston.
We always have the Dart block in stock and can do a very nice short block with the Eagle 4340 steel crankshft, 4340 H-beam rods, SRP or Mahle pistons, heat treated bearings and plasma moly rings with a hydraulic rooler camshaft and Ford racing double roller timing set for about 5000.00. It is zero balanced which by far the best for stroker cranks. We are also a SVO dealer and can help with thier parts as well. Good luck with your project. Keith Craft

We built a BOSS Block in december Serial #3xx for a 347. The tech line was fumbling for info at that time.

We figured out the following HEAD gaskets work well; FMS-M-6051-S331 (available where FRP are sold, buy 2 sets as these go on BO freq.) we used this in concert with an edelbrock performer RPM AL head.

Head stud kit ARP ; ARP 155-4001 FE Kit, works fine. Block bolt(head bolt) holes are deeper and threaded lower than a regular 5.0L/302 block.

The block plug kit came installed in both blocks we have bought. it also came with a bag of goodies. (pins, plugs)
the block is awesome, hence we are using it for my 331 (final CI TBD) for my MkIII SPF.

The block is also tapped for a clutch pivot stud, and the sheet metal frogs for holding the roller lifter spiders in place.

Sooooo The price of admission is higher, as a factory fresh 5.0L block is about 600, and the Boss punches in at 1800 but as a nice foundation for a 302 form factor engine.

Thinking out loud, I am wondering if they could come up with a BOSS 351W block to make 427Ws easier and beefier.

Have yours built; with the exception of the roush, crate motors are for camaros...

--Steve

Check out the March '08 issue of HRM. They provide a fair amount of info on the 331 Boss crate engine with comparative dyno figures for GM and Chrysler engines. Bore/stroke as tested is 4.125/3.100, which makes for a high-revving small block. One red flag I noted was the compression ratio. The 12:1 CR moves this engine out of the pump-gas range. I'd like to see figures on a 10.5:1 engine.

The 331 in my GT40 was dynoed at 385 hp on pump gas. Block is the old SVO with dimensions similar to the Boss. Crower crank and rods are used as are Dart heads.

I really like the Aussie CHI Funnelweb intake used on the Boss crate piece. I think this manifold is available from World Products.

331 cid stroker—a hand-assembled, tire smokin' powerplant built by master engine designer Steve Bramlett.
302 hydraulic roller block with main girdle (rated at ±400 bhp)
balanced & blueprinted
10.0:1 compression ratio—runs on pump gas
Cobra valve covers
650 Holley dual line
Edelbrock RPM Air Gap intake
Lunati rotating assembly with forged steel crank and pistons
Comp Cams hydraulic rolling camshaft and lifters
roller rocker arms
double roller timing chain and gears
TFS Twisted Wedge heads

http://www.cobracountry.com/cobra4sa...2a-540x385.jpg

I love mine!!

Now back to the BOSS 302 block.... 331 stroker for my road racer, 12.5 to 1 engine, 7,000 rpm chip, rarely hit more than 6500 rpms......

I'm really tired of pulling the motor and replacing rear main seal.... gotta pull it for the third time now.....:CRY::CRY:

Sitting and running,regardless of rpms, it leaks NOTHING, but get it on the track and after two or three laps, oil coming out the bell housing, leaking all over the exhaust system and it looks like I got a 2-stroke motor under the hood.......2 different folks have looked at it and put in the rear main seal with the same result...

First engine was built with a factory 1969 302 block, when I took it down to freshen it up after 2 long hard seasons of racing, I decided to "upgrade" to the BOSS 302 4-bolt main block and have had nothing but headaches ever since.........never leaked a drop of oil with the old block!!!!!!!!!!!!!!!!!!!

I used all the same components out of the other motor and they all went into this new block, that's the only difference from the first motor........the block, same heads/cam/intake/crank/rods/pistons/canton road race pan/same everything.............and I put the motor together the same way I did the first one!!!!!!!!!!!!

HELP, I'm using the standard factory 1-peice rear main seal as per Ford's directions, anyone have any ideas??????????

David