i wanna build a boss with a difference- 351 block destroked to 302 cubes or there abouts - to slow piston speed- planning on cam with max power 7500 to 8000 rpm -xc 302 clev heads -on lpg- aiming for reliable 600hp -do not want to change requirements-do not want to hear/read can't do it because blah blah blah just how to do it and if there are going to be problems how to get around them-will be going into eb xr8 street car

Anything can be done, but it won't be cheap. You will need a custom crank, custom pistons, aftermarket inlet manifold, and a fair bit of work (money) to make the clevo heads seal on the windsor block. Hope you have plenty of $$$$ to spend.

Hey that is different, but it would depend on what you are trying to achieve. If you are only trying to run 302 pistons in a 351 (W) you might as well stay with the standard 302 block. I am relatively aware of the clevo stuff and I am a bit of a train spotter on the 351m400 from buying a car with a 400 in it and they are like that too with the 351m running a a destroked crank and different pistons. Exactly the same as the 302c is to the 351c.
I believe the 351w is a taller deck than the 302w? If you are trying to obtain something with the same bore and the same stroke as a 302w, you will definitely have bragging rights, but you may be able to achieve what you want in a far more spectacular fashion staying with a standard BOSS (as if they are standard) type configuration and use your money to get the revs you are after.
The guy I bought my 400 parts from is Timothy Meyer (TMI) in the states, and he has all the applicable top end (manifolds etc) to do a clevor (BOSS) about as easy as you can get in one spot, but your major sticking points will be the manifold and crank.
Price motorsports (http://www.pricemotorsport.com/Intake_A ... pters.html) in the states do all sorts of things to adapt between engines, heads and manifolds, but they are in the region of $250-300US and they actually have an adaptor to suit your application (AP-08?). Get yourself a good book on ford applications and see if a crank with the right throw cross's over as you may only need an offset grind. For example the 351m-400 run the same size main bearings as the windsors, they are bigger than the rest of the cleveland family they are based on. They do have exclusive sized rods and applicable pistons that make it more problematic to rebuild than a standard 351c for example. you really need an old school engine rebuilder that know all the different stuff that could be modified relatively easily (read cheaply) to achieve what you are after otherwise you could spend a lot of money and have an engine package that is inferior to something more readily buildable.
like I said if you are after something with the same stroke and piston diameter than you might as well stay with a 302 BOSS type set up. If you are after something with a larger diameter piston and shorter crank throw, that is something completely different altogether. I don't know if that is acheivable in the block configuration you are after and you will have to wait for the guys with the knowledge on the Windsors to help out. In my dealings withe the 400 in my galaxie there was a few naysayers suggesting I dump it in favour of either a standard 351c or a 429-460, but at the end of the day, cost was a bit of an option and it was just easier staying with what I had due to it all so I know what it's like to be told you shouldn't. Good luck and merry xmas

Just FYI, 289/302/5.0 windsors have 2.25" main journals, 351W (and 351M/400) has 3.00" mains, 302/351 Clevo has 2.75" mains.
Hope this helps.

If money is no object, think about a Dart block, with 8.7" deck height, 4.125" bore, 3.25" stroke, CHI 3V heads, for a high revving 347 cube screamer, with enough torque to move a heavy car at lower revs...... But you will need $$$$$$$$

What about the big end? the 351m-400's and 351c's run the same rod bearings

I didn't worry about that, as I figured he would need to decide on a crank & block first.
But...
289/302w = 2.125" big end journal
351C/351W/351M-400 = 2.310" big end journal

Conrod length is going to be determined by deck height, piston compression height and stroke.
The pistons will need to suit the clevo head, for the correct valve pockets

I reckon if you have a 351 clevo already, use what you have, upgrade the rods and pistons, and get a good balance job. It will rev to 7800 easily enough, provided you spend the dollars on the heads and valvetrain.

It sounds like he wants to go windsor though and go the whole Boss way but use a 351w block. Balance bottom end, stick with a standard 302w with the clevoheads and stuff from Tim Meyer, price motorsport adapters and you could fit injection/manifold from a mustang ex US. heaps of cheap stuff over there for just that thing. would be a sweet number. Sorry Daboss, I know what your idea is with the destroking thing, most motorsport guys will know of an engine package with that in mind, but it involves doing it to an engine that doesn't have a configuration like that already. with the windsors and clevelands, they already exist (sort of) 351/302 etc. the smaller Main diameter of the 302w vs 351w would be more desireable due to reduced surface speed (smaller diameter = smaller circumference). I know it's a ford forum but as an example a good friend (yes I do have friends!!) who is an old Holden nut,( but has also thrashed quite a few falcon 6's back in the day, just not any 8's), still reckons the good old 253 used to be a sweet revver over most of the 308's he played with/drove crashed etc. even though a lot won't touch them with gorse because they are not percieved as powerful as the 308's. Theres a thought. Why not sleeve down a 302w to a smaller piston and try for a 250ci-ish size motor. if you are after revs vs torque that might be a fun (expensive) way to go and very different. Probably a lot easier to as the rest of the engine would be more readily available. the thicker sleeves would give it a bit of strength and the lighter reciprocating weight would mean less strain on the bottom end. with a lighter/smaller piston, it could rev like the clappers. you could still build it like a boss too just for name value too. would be more a sacrifice of torque to get horsepower though.

The only problem with going smaller in the bore is getting the valves to fit. Clevo valves are too big for a 302 as it is, with a smaller bore it could get messy.....

If I had an unlimited budget, I would use an 8.2" deck height dart block, with 4.125" bore, use a 3" stroke crank, and get 320-odd cubes, with a set of CHI's with Ti valves and all the good stuff, with 8-stack efi like a V8 supertaxi. It wouldnt make much down low, but it would rev like s**t and make bulk power up top... But I dont have a spare 20k lying around. Or anything to put it in.

9.2" deck alloy dart block, sleeved to 3.9", 3.6" stroke, big heads, high lift/low duration cam.
wait that sounds familiar...

Why would you sleeve it down to 3.9" bore? A lot of work (money) for little gain, IMHO.

so is trying to turn a 351w into a 302w
it was an LS1 joke.

come on, 302ci 351w with factory clevo heads spinning to 8000rpm making a reliable 600hp on gas.
it's a joke thread.

okay some of you are getting close i suggest you read smokey yuniks book on power secrets,he built a 208 ci chev-350 block destroked etc it produced over 1000 hp admittedly with a turbo.
slow piston speed by increasing the length of the rod is my what i am try to achieve with my combo,that way i can rev the motor higher and it wont grenade, the piston will stay at tdc for longer so in theory should produce a bit more power.the 302 bore stroke ratio is really good so i want to stay with that but with the longest rod i can fit
the heads will be suitably modded or dart iron heads will be used just prefer clevos as half the work is already done
i have looked at dart blocks is it legal to run them in vic

Some points....
1. A Boss 351 is a cleveland engine.
2. A 302C crank will have your Boss 351 down to 302ci and smaller still if you offset grind it.
3. Dart don't make a cleveland head but CHI,AFD,Edelbrock and TFS do.
4. You want to make 600hp and you are worried about legality?

Sounds to me the ideal combo is Dart 8.7 deck block with 1.25 bore, custom pistons which should cost around $1500 / $1800 a set..
With the longest rod you can find... The custom pistons will allow a good rod combo with big dia
pin... Why do you want to use Iron heads ?? There's PLENTY of GOOD alloy heads for Clevo and Windsors...
The 302 Chev made good power for it's size.. I assume this was what basically built with the 350 base engine..
All engines will perform with GOOD heads and valve train...
600 h.p is beyond a std 5.0 block which I is why your after a destroked 351...
The long rod 8.7 block is just the answer ...
http://www.dartheads.com/products/iron- ... ck-8.html#

Here's a short block combo..
http://www.dartheads.com/products/short ... ilder.html
Oh yes the block is a replacement block isn't it... It's legal but don't shout about it.. It's the bits and pieces they may not like.. Heads especially...

Only if the companies made a EFI and carby manifold for the 8.7 deck block there would be so many of them getting around with some decent cubes.......

I guess if the market ask for it then it will come but then we need a DART SHP verion of 8.7 as well.....