Cast pistons ring pack won't last long with those piston speeds...thing will be leaking 25% in a month or so with a 4.150 arm in it

The idea was that with the re use of existing oem parts the only real major expense was the cost of the crank. Here is what I observed: New stroker crank $600. New KB smog pistons on ebay right now- $120 plus $30 shippping. Reuse existing rods. So thats $750 so far. Thats what I was looking at. Obviously if there is another grand in machining and what not its not feasible over a modern kit. Someone mentioned piston to valve clearance is an issue- I assume this is why the old Bouchillion kit recommended the mopar 484 cam. Anyway the thought was an econmical 500" motor with stamped steel rocker arms and a long duration hyd flat tappet cam. The traditional chevy grind cams for mopar dont have a lot of lift for their duration and PAW used to have their in house name brand cam/lifters for under $125.

I used the Summit 488 in a stock 9:1 440 good cam. The 484 will bleed compression and you will need a 3000 stall and at least 3.91's. Summit cam kits were on sale a month or so ago for $62! w/ lifters.
Why not look around? somebody is probaly selling a used stroked short block you can get for 1/2 what it costs to build.

There's some pretty good points made here, a well built lighter bobweight 440 with custom slugs might be a better bet overall. Pretty easy to run 11's with an old school 500 hp 440, even on pump gas. Plus if you build it with decent compression flat tops you can upgrade the heads to closed chamber E-heads/stealths or SR's later on and probably pick up another 40-50hp and 500-700 more RPM which would morethan close the gap on a stock cast heavy slug 490....

What body is it going in? depending on the weight and gearing sometimes it's a better overall fit (in terms of real world ET) to trade cubes for RPM. A dollar in the heads can be worth 3 in the short block. Most stroker guys do both but I can see certain apps where a freight train torque motor can be cheap and fun. A good example is a 500 caddy in a 78-88 GM A body, it's all done by 5000 rpm but man it's fun getting there.

What about the old school 3/8s offset ground stock crank,chevy 7.1 rod,custom piston = approx 470 CI. No welding req and around 2375 bobweight. That was one of the old school combos built in the 90s by a local builder here in VA and may be cheap to build today IF you could still get the pistons and the crank work for a fair price. Its kinda hard to beat the price of avail kits these days.

I am not building this engine. It was just a thought. I have a 71 Demon in storage. I can tell you that when I was active in the car hobby I drove my car 5 months out of the year- under 1500 miles in that time. No strip time just fun street blasts, cruises and errands. Thats why a poor mans stroker is appealing to me. I read the smog pistons are perfectly fine for max 5,500RPM. The chevy grind cam- like a Comp Cams magnum 290 has a lift of only 501 but duration of around 245. Goal would not be to run 10s or 11s but a super torquey RELIABLE beast of a STREET ONLY engine. I live 40 minutes from Martin Dragway but even when I was driving a car I just never made it there. (Demon is in storage until 12 year old daughter turns 18 and some money is freed up)

I remeber seeing a number of people selling stock cast 440/400 pistons on ebay for cheap. Been some time since I searched, but they were like $18-$20 each.

I looked into building a 400 block/440 cast crank stroker with oem cast 440 pistons. Wont achieve 500 cubes, but its probably the lowest $ stroker you could build. With cheap ebay pistons, and stock crank and rods, the biggest costs would be piston reworking (valve reliefs and cam clearance) and your general machine work and balancing.

Read here: http://www3.sympatico.ca/big-d/460.htm

I ended up with some 440s so I went that direction instead.

There are reasons for everything... simply sticking misc part designed for stock stuff into a hole they will fit in is not always the best course of action. In the case of pistons... some numbers that might clarify.
stock 400 stroke (3.38"):
mean (average) piston speed at 4K= 2253feet per minute At 5500rpm= 3098FPM
Max piston speed at 4K= 3648FPM At 5500rpm= 5016FPM

4.15 stroke:
mean piston speed at 4K= 2756FPM at 5500= 3804FPM

Max piston speed at 4K= 4500FPM at 5500= 6200FPM

The reason cast pistons are not part of stroker kits is because they simply are not designed to withstand high acceleration and deceleration rates the longer strokes create. almost 25% more max speed, but accelerated and slowed down in the same distance. The pistons will simply flex for a while, then either the rings begin to lose seal as the ring lands deform, or the pin rips offf the domes. You can help the mean average speed by keeping the peak rpms down. But you can't drastically affect the rate of acceleration because of the stroke. So, you have a package that limits lift because of valve reliefs, and rpm due to materials. I understand the "do it because I think I can" mentality. But truthfully, I dont see why someone would want to unless you have a full machine shop to play in for free. Then it might be fun to see what could be done.

Sometimes I like to ponder a possible buildup for my Demon. Not having spare money means a purchase here and there with parts put in storage till the day arrives it can all be put together. The new kits are the way to go and are a great value. 15 years ago the cost was more than double to do a stroker than it is now. The poor mans stroker is not cheaper if there is oddball overboring/machining required to the block and pistons. The interest to me is the concept of buying new $600 stroker crank - $135 new pistons, inspect parts and assemble. Comp Cams magnum 290 (244dur 501 lift) stamped steel rockers, new valve springs, Torker intake and big holley. Engine assembled with already owned parts and parts available used. Stock but sound OEM iron heads with the goal of stealth heads in the future.

Good point about the piston speed, if I were doing a low buck torque motor I would open up the bores about 1/2 a thou (.0005) to compenstae for the extra heat generated from the higher than normal piston speeds and then cam/port the motor to limit the motor to about a 4800-5000RPM power peak with a redline of about 5300-5500rpm. I'd also shorten the factory pressed pins about 1/2 inch to save about 50 grams. A 400 piston is about 80-90Grams lighter than the 440 and the skirt and ring supports are roughly the same, in terms of bobweight my combo on paper comes out a good bit lighter than a 440 Magnum and lots of those got spun to 6200-6500. But remember (and a lot of people don't realize this) the cylinder pressure stresses actually drop off as the VE plummeted with the old heads that were already spent, even though the Frictional HP losses continue to move upward with RPM. All in, I think a low buck 490 built this way could safely operate to 5500, but again you want to 'build-in' your rev (piston speed) limiters to minimize the potential for sealing losses, and building to make sure the VE drops off like a rock at a moderate RPM is really a good way to do that. The motor will continue to accelerate but the RATE of Acceleration drops off because the pumping efficiency is spent. I can think of a lot of apps where a motor like this could be a lot of fun on the street....but Like Clint Eastwood says "you gotta know your limitations!"