Has anyone out there built, has in progress or is planning on building a performance Polyhead engine. I know this is not a popular subject but my first project is complete and running and I'm ready to plan my second engine. Nick
yes, all small block mopar stroker cranks will fit the poly motor, built one for my '64 dodge about 5 years ago. Best intake I could find (that wasn't $1200) was the factory dual four bbl off of a '57 (i think) 318. I'll dig up the build info and post it as soon as I can track it down.
Here's a 318 to 402 kit: http://www.speedomotive.com/ps-648-13-318-poly-to-402cid-stroker-kit.aspx. You might also want to check this out: http://www.jalopyjournal.com/forum/showthread.php?t=81380.
That's an awful good price for a stroker kit that is made for an odd engine . That just opened up an all new area for the Mopar people . I do know that there are Y block stroker kits also . How about the Olds engines people ? I also agree , anything is better than the orange crate engine ! Retro Jim
My 1st project is complete using a 1964 318 block, bored .090", stroked to 3.58" making 359 cu.in. A Callies Dragon Slayer crank, Crower rods, CP forged aluminum pistons 9.5 CR, Racer Brown ST-14 flat tappet cam, Weiand 7503 intake, Rev valves, Mallory 57 distributor, & TTI headers. On the dyno it made 392 hp @5700 rpm, 392 tq. @4200 rpm. Nick
I have started on a stroker Poly for my 66 Phoenix/Fury. I will get some photos of the goodies that are going on it. Won't be as pretty as your one though.
You are my hero! My '64 318 is mild... bored .40 over with a mild cam, 3x2's and lake headers... No dyno yet... but guessing arond 300 give or take...
the question is, what did it cost you to build that motor to make that power? could you have bought a 426 hemi?
Wow. Really makes me wish I still had my '65 Fury lll. When I had it 25+ years ago I didn't have a clue where to find performance parts for it, let alone if any had ever been available. You say its bored .090 over ? Did that require sleeves ? Very impressive engine !
Maybe you've seen this magazine how-to article: http://www.moparmusclemagazine.com/...poly_engine_more_power/poly_tube_headers.html Where they build a 318 poly into a 402ci with 442TQ and 397HP.
The only thing special or "odd" about that kit is the piston's and rings! The 4" stroker crank is the same as one for "LA" 318's/340's (and it is cast, a downgrade from the stock forged crank) 6.123" rods are the same as 318's/340's Rod and main bearings are the same All the rotating parts to build a "402" poly are off the shelf for a 68-91 318 except for the pistons. And I'd wonder about those too, since the poly 318 shares the same bore as a LA based 318, only the valve arrangement is different. I wouldn't be surprised if you could use certain types of LA 318 pistons too. Mopar types have been using forged cranks out of poly 318's in LA 318's/340's for quite a while, nice upgrade from the later cast pieces for a high power build. Per Allpar- "Bill Watson noted that the LA-based 273 used the poly (A) 318 crankshaft, bearings, bearing caps, vibration damper, and conecting rods. The 273 and 318 both had a 3.31" stroke. Pistons were different, though, as the bores were different while camshafts could not be shared due to the different valve arrangements.Read more at http://www.allpar.com/mopar/a-engines.html?ktrack=kcplink" Now, that addresses pistons for a 273, but the LA 318 had the same bore as the poly 318, at 3.91".
The car and some bolt on's. Fountain finned valve covers, Weiand manifold, Eldebrock carby ( thanks to the Aussie dollar about $370 delivered to my door ) and disc brakes for the front.
Have done a 318 to 355. I helped a friend do it and had him do most of the assembly. We used a 360 crank and had it machined to 318/340 main journals. Used off the shelf 060" oversize Dodge truck pistons from slivolite. They are a set of pistons believe it or not listed for A or La both as they are low compression and have no valve reliefs. I was able to match their weight easily to a stock 360 piston from the engine that we got the crank and rods from. If you like i will get you the number. We actualy got them through Summit as they are a silvolite dealer. Because we ran a bigger cam I did flycut the pistons slighty just for safety but that was a fairly simple job and did not take us long. Because we used the 360 crank and rods and balancer and flywheel and I kept the pistons weights the same we did not require a rebalance. Engine is installed in a 65 fury with "Three by the Knee" We converted a set of Ford truck 390 headers by swapping flanges and we had to move two pipes slightly for starter clearance and one for right side torsion bar but not much. Car is running (Fury two four set up) I also had a hydraulic cam made (340 68 stick lobes on the old mpar core) and we had manton make a set of shorter pushrods (Mopar lifters are different length hyd vrs solid) which are the weak spot in these motors anyway. Car is currently being readied for paint. Cost was very low. Cam and crank work was about $300 my cost(tradesman) Pistons were I think $97 and pushrods were about that as well I believe. Don My first street driven hot rod in fact my first car when i was 16 was a poly. I always liked them. Here is my old one when I was a "jungen." PS dont be concerned about the 360 crank being cast or even the mopar 4 inch . Thinking you "must" have a forged crank in a street piece or even a bracket engine is the equivalent of thinking you need titainium valves in your lawnmower. A cast crank will stand without failure at least 600 HP. (Probably more truth be known. Mickey Thompson made and used them for his strokers. People forget that)
amitygravel, The plan on this build was a 4" bore with as close to a 3.60" stroke as possible for the best rotating combo, 3.58' stoke was real close. The sonic test to this block was good to .110" allow for the .090" bore. Let me first say that my engine builder did all the calculations. Nick
Why not just put poly heads and cam in a 360? I put 273 top end on a poly 318 years ago, put it in a '64 'Cuda and it ran great for years. No reason why going the other way won't work too. BTW, that 318 surprised a lot of Mustangs!
You can go one way, but not the other, or @ least not w/o a huge amount of work. There's threads on it on the forum @ www.moparmarket.com
4woody, I know this 402 Poly engine build, it was a good build and got many interested in working on this engine. I have made an overlay of the dyno sheet with my 359 Poly with some interesting results. That @5250 rpm the 402's hp/tq lines crossed. That @5250 rpm the 359's hp/tq lines crossed. That @5800 rpm the 402 and 359's hp line met and equaled. That @5800 rpm the 402 and 359's tq line met and equaled. The 402 had 42 more cubes, higher compression 10:1 vs. 9.5:1, bigger cam, (I think) 290/.492 vs. 266/.486, larger intake valve, 2.02 vs. 1.96. The 359's heads have a lot of flow work. (If my old memory serves me), I remember that a 1.96/1.60 valve combo will flow more efficiently 359 cu.in. than 2.02/1.60 valve combo flowing 402 cu.in. With all the good porting, a 1.5 ratio, and equal cams the Poly heads just get maxed out at 402 inches. The shorter stroke also revs real quick and holds a flatter torque line. The 359 @3000 rpm made 365tq. and increased, remaining above through 5600 rpm. I know the man that built the 402 and I know that the next Poly he builds will be a real eye opener as to what this engine can do. Nick
R Pope, I've heard talk about this kind of swap but never heard from anyone that had done it, or even knew how to do it. Both the A-318 Poly and the LA-318 Wedge are proven engines in and of themselves. Just last month I stopped a fellow club member's son from putting a A-318 Poly in his '64 Dodge Dart. I found for him free a '68 LA-318 Wedge which he will swap in with much less work. How did you mate the LA-273 wedge heads to the A-318 Poly block and what intake manifold did you use. As far as using LA-360 heads & cam on my Poly, I can't see how they would interchange. Nick
Hi Nick, good to see you on the Hamb! The King of the Poly is Gary Pavlovich (as noted in one of the links) (he is a casual member on this board), if you are even thinking seriously about one of these give him a call or send an email. Plenty of parts available from the usual sources (including yours truly) for a stroker Poly. A 4" cast crank is only $325, and the 4" forging is only $810. Forged pistons are available so you can mess with the rod length. Our Auto-Tec forgings are only $630/set. We can regrind your cam, occasionally we have cores available. Yeah, its a shameless plug but, just letting y'all know there is no parts shortage. Gary
Nick I have done the offset grind on the 360 crank to get 3.60 stroke. (I also build or built 380 cubed 340s using that crank offset to 3.6. ) Don By the way "THE KING " Gary P is a personal friend. I just talked to him last week. (phone) Also BTW all engines have the same HP as torque at 5252RPM. why? Because the formula for hp is Torque Ft LBS X RPM /5252 so when the engine hits 5252 RPM the two are equal (5252/5252) and cancel leaving torque and HP being the same.
Hello Don, I've followed your text for several years now, everyday something new to learn, thanks for the info. Gary and I also speak by phone and will be again soon as his new build comes along. Do you still have that beautiful '63 Polara? Nick
Nick, The heads actually bolt on, the only differences in the blocks are in the pushrod clearances and water passages. I looked at dropping a set of Poly heads onto a 360 about 20 years ago, even had it mocked up; but got onto other things and never finished the project. I had intended to run external coolant hoses to the heads and block off the coolant transfer passages in the head surface (that area doesn't exist on an LA block). I asked R Pope how he did it in another thread, and he apparently just slapped them on and went...still not sure how that worked.
63 Dodge (actually it is a Canadian 440 series (Ply style interior) Yeah but I am thinking of selling it. i have had it 10 years and have put 40,000 miles on the 426MW. I am into my sr dragster now and having so much fun I have kinda lost interest in the 63. I am though replacing the lower A frame bushings as time has caught up with them. Gary P phones sometimes and talks well into the night. I try and encourage him as much as possible. I always liked polys. Don Don
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