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318 Poly question #2977166 10/22/21 10:32 AM 10/22/21 10:32 AM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	Anyone know off hand what the piston height is on a stock 318 poly? Thinking about what it would take to build a zero deck motor for quench. "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: 6PakBee] #2977243 10/22/21 01:19 PM 10/22/21 01:19 PM
Joined: May 2019 Posts: 6,225 nowhere S Sniper master
Sniper master S Joined: May 2019 Posts: 6,225 nowhere	Can't answer the question, but that combustion chamber might make quench tricky.

Re: 318 Poly question [Re: 6PakBee] #2977314 10/22/21 04:28 PM 10/22/21 04:28 PM
Joined: Jan 2005 Posts: 12,419 Kalispell Mt. H HotRodDave I Live Here
HotRodDave I Live Here H Joined: Jan 2005 Posts: 12,419 Kalispell Mt.	Zero deck is easy, about .035 ought to do that but quench? Even max milling the head will give no meaningful quench pad, you would have to weld em up and mill them flat again. Another option would be to use an end mill and machine some flat areas in there and get custom pistons with a matching raised area... I love what quench does for an engine but even I wouldn't bother with it for the gain you would get on that engine. I am not causing global warming, I am just trying to hold off a impending Ice Age!

Re: 318 Poly question [Re: HotRodDave] #2977324 10/22/21 05:15 PM 10/22/21 05:15 PM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	Okay, so trying to get quench is a stupid idea. No problem, I'll move on. Thanks for the frank comments, saves me continuing to pursue something that is questionable with this design. Unfortunately it's been 50 years since I was inside a poly and I can't remember anything about it other than if you miss a gear and you see the tach going past 6500, you will bend a lot of pushrods. "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: 6PakBee] #2977331 10/22/21 05:47 PM 10/22/21 05:47 PM
Joined: May 2019 Posts: 6,225 nowhere S Sniper master
Sniper master S Joined: May 2019 Posts: 6,225 nowhere	Originally Posted by 6PakBee Okay, so trying to get quench is a stupid idea. I believe it's the Marines that say if it works it ain't stupid. Not a stupid idea you have, might be tricky to implement and the gains may not make it worthwhile, but if you did it and it worked as you hope it's not stupid. Expensive, that is another story there.

Re: 318 Poly question [Re: 6PakBee] #2977391 10/22/21 09:34 PM 10/22/21 09:34 PM
Joined: Aug 2003 Posts: 43,126 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,126 Bend,OR USA	Mopar stop making those motors for a reason, they weren't efficient or powerful The 273 L.A. motors made more power and got better mileage than any of the 305, 318,325, 331 or 354 C.I. poly motor in any of the Mopar cars or trucks Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: 318 Poly question [Re: Cab_Burge] #2977404 10/22/21 09:46 PM 10/22/21 09:46 PM
Joined: Jan 2003 Posts: 10,538 Freeport IL USA poorboy I Live Here
poorboy I Live Here Joined: Jan 2003 Posts: 10,538 Freeport IL USA	Originally Posted by Cab_Burge Mopar stop making those motors for a reason, they weren't efficient or powerful The 273 L.A. motors made more power and got better mileage than any of the 305, 318,325, 331 or 354 C.I. poly motor in any of the Mopar cars or trucks You are talking about the early 60s here, Mopar put dual quads on those A motors and they made almost as much HP as the early Hemi's did. The reason Mopar quit making them was because they were too big for the downsized engine compartments, and because they were too expensive to make. Mopar (and most everyone else) wasn't too concerned about efficiency until the mid 70s gas shortages..

Re: 318 Poly question [Re: Cab_Burge] #2977451 10/23/21 01:21 AM 10/23/21 01:21 AM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	Originally Posted by Cab_Burge Mopar stop making those motors for a reason, they weren't efficient or powerful The 273 L.A. motors made more power and got better mileage than any of the 305, 318,325, 331 or 354 C.I. poly motor in any of the Mopar cars or trucks It would be interesting to see how the poly heads flow compared to an LA or Magnum. I would think that would be the major difference between the engine families. And just looking at the heads, one would think, and I know this is an assumption, that the poly heads would flow better. "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: poorboy] #2977454 10/23/21 02:30 AM 10/23/21 02:30 AM
Joined: Aug 2003 Posts: 43,126 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,126 Bend,OR USA	I should have included the two barrel L.A. 273 compared to the two barrel Poly motor made more power per C.I. and got better mileage than any of the Poly motors made. I've owned and driven cars with both motors, the L.A. motors are way better than any of the those early Poly motors that Mopar stop making in 1966 As far as the size of those Poly motors compared to the L.A. motors how can they be bigger if they both can use the same timing sets as well as those timing sets fitting on the 1957 and 1958 392 Hemi motors? I'm almost positive that the 1962 and later 318 Poly motors and 318 L.A. motors have the same blocks and crankshafts BTW, the Poly motors where NOT L.A. motors Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: 318 Poly question [Re: 6PakBee] #2977460 10/23/21 03:20 AM 10/23/21 03:20 AM
Joined: Dec 2009 Posts: 20,630 in a cattle trailer down by th... G Guitar Jones Paddle faster! I hear banjo music!
Guitar Jones Paddle faster! I hear banjo music! G Joined: Dec 2009 Posts: 20,630 in a cattle trailer down by th...	I've seen flow numbers for the poly heads in the past and even ported versions. Unimpressive to say the least but not horrible. You can use the LA stroker cranks in them and you might be able to bore some blocks .100 over. Unless you just want to do something different they probably aren't worth the effort. "Follow me the wise man said, but he walked behind" '92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon! 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.

Re: 318 Poly question [Re: Cab_Burge] #2977472 10/23/21 07:40 AM 10/23/21 07:40 AM
Joined: Jan 2003 Posts: 1,335 Oregon E earlymopar pro stock
earlymopar pro stock E Joined: Jan 2003 Posts: 1,335 Oregon	Crankshafts yes but the LA block design is a lighter weight "thin-wall" casting. Poly blocks also have deeper reliefs on the intake side of the deck to clear the straighter pushrod angle required by the Poly heads.

Re: 318 Poly question [Re: earlymopar] #2977476 10/23/21 07:53 AM 10/23/21 07:53 AM
Joined: May 2019 Posts: 6,225 nowhere S Sniper master
Sniper master S Joined: May 2019 Posts: 6,225 nowhere	https://www.motortrend.com/how-to/426-cube-318-poly-can-outgun-hemis

Re: 318 Poly question [Re: Sniper] #2977511 10/23/21 09:41 AM 10/23/21 09:41 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	Nothing wrong with Poly questions. Semi-hemi engines don’t squench like wedgie engines. Stroking is the easiest way to ‘up Poly compression’ methinks! Folks have been spoilt with LA engines for over 50 years! But the lowly 318 Poly can be made to work... The old trick was to overbore to 4 inch and turn down a 360 crank. But now we have high compression 402 kits for the serious Poly Folks. 400 horses not beyond a stout Poly build. We are moving on to a 500 horse Poly build now, with a blower... Dare I say it? Chevrolet intakes and headers from the LS range... Last edited by Gtxxjon; 10/23/21 09:44 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977512 10/23/21 09:43 AM 10/23/21 09:43 AM
Joined: May 2019 Posts: 6,225 nowhere S Sniper master
Sniper master S Joined: May 2019 Posts: 6,225 nowhere	Originally Posted by Gtxxjon Nothing wrong with Poly questions. Semi-hemi engines don’t squench like wedgie engines. Stroking is the easiest way to ‘up Poly compression’ methinks! Folks have been spoilt with LA engines for over 50 years! But the lowly 318 Poly can be made to work... The old trick was to overbore to 4 inch and turn down a 360 crank. But now we have high compression 402 kits for the serious Poly Folks. 400 horses not beyond a stout Poly build. We are moving on to a 500 horse Poly build now, with a blower... Read the link I posted, 551 hp no blower needed.

Re: 318 Poly question [Re: Sniper] #2977515 10/23/21 09:45 AM 10/23/21 09:45 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	Read it many times and those parts are way too exotic for ‘shade tree’ mechanics like me. I have contacted these folks for help and advice, but no luck. Biggest problem was a trick roller camshaft, they are rarer then Unicorn tusks... Compcams have made them for the selected few, the rest of us have only flat tappets. Biggest we have found is a 'Custom ground' Schneider with a 0.525. This stuff is so rare you have to 'GO IN PERSON' and BEG!!! Its a long way from London Town to the West Coast... So it’s an ‘old school’ blower for us now to find another 100 horses... Last edited by Gtxxjon; 10/23/21 11:09 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977521 10/23/21 10:01 AM 10/23/21 10:01 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	By a strange coincidence the fat intake flange method of port raising was done to my race engine in the 80’s. Back before aluminium heads were available for 440 engines it was the only way forward. The Ovalport intake was developed by Mother Mopar in the 60’s too. I have here a set of Big block heads with that same design for a Nascar development engine. Ovalport IN, D-port OUT... All that is Old is NEW again... Last edited by Gtxxjon; 10/23/21 10:21 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977525 10/23/21 10:18 AM 10/23/21 10:18 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	My Rob Loring 452ci engine had the 'raised ports back in the 80's. 5/8 inch flanges and the ports raised by 1/2 inch with directional runners. Engine made 550 hp and ran in the nines with a street Dart. Very trick stuff indeed for the ERA! Last edited by Gtxxjon; 10/23/21 10:20 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977532 10/23/21 10:40 AM 10/23/21 10:40 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	The wonderful Gary Pavlovich has been the Poly Guru, for as long as I have known! He supplied all the knowledge and the parts for our 402ci Poly stroker build. Work underway for the new Schneider camshaft and better valve seals. The biggest Poly flat tappet ever made @ 0.525'' with old school Crane dual valve springs... Gary's custom made valves at 2.02'' and 1.60'' with 11/32'' stems. Sure look much more exotic than a LA head lol... Last edited by Gtxxjon; 10/23/21 11:05 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977533 10/23/21 10:48 AM 10/23/21 10:48 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	Facebook and ''62 to 65'' sites for Poly POWER! Some crazy OLD folks take POLY very seriously indeed... Me I'm just a DYNO-SNORE ps. the 2 bolt POLY caps were a little suspect so the last job I did before my retirement was a 340 cap conversion! (just in case we hit the 500hp) lol... Last edited by Gtxxjon; 10/23/21 11:03 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977576 10/23/21 01:22 PM 10/23/21 01:22 PM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	I sure appreciate all the replies. I think I'm going to add this to the already bulging project list simply because you just don't see many polys any more. It's the original engine in a '65 Belvedere II I have and I think I'll keep it that way. Thanks again. "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: 6PakBee] #2977585 10/23/21 01:56 PM 10/23/21 01:56 PM
Joined: Jan 2003 Posts: 20,751 A collage of whims topside Too Many Posts
topside Too Many Posts Joined: Jan 2003 Posts: 20,751 A collage of whims	Anyone contemplating building a Poly should pick up Victory Library's "Chrysler Poly Performance" - I think a member here wrote it but can't recall his name. It's a great resource & delves into a lot of stuff. I've had a few - '63, '64 & '65 318s - and they didn't seem very octane-sensitive to me, they'd run on anything. Not sure I'd worry much about improving quench. Then again, they were stockers, never pushed the CR, just drove them. Decent street motors, and not everything needs to make 600HP. They used heavier castings than LA is what I've heard, and metal costs money. Chrysler would do anything to save a buck. It's tempting to think "BBC" when looking at the valve arrangement, but ported Poly heads seem to max out at around 250/200 CFM I/E. Subtract about 50CFM each side for stock.

Re: 318 Poly question [Re: topside] #2977602 10/23/21 02:45 PM 10/23/21 02:45 PM
Joined: Aug 2003 Posts: 43,126 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,126 Bend,OR USA	For those that don't know why Mopar designed and built the Poly motors was for using a single rocker arm shaft to save money over using the hemi motors heads with dual rocker shafts and rocker arm spacers and spring on the same designed blocks on the Chrysler, De Soto and Dodge cars Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: 318 Poly question [Re: topside] #2977608 10/23/21 03:13 PM 10/23/21 03:13 PM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	Originally Posted by topside Anyone contemplating building a Poly should pick up Victory Library's "Chrysler Poly Performance" - I think a member here wrote it but can't recall his name. It's a great resource & delves into a lot of stuff. I've had a few - '63, '64 & '65 318s - and they didn't seem very octane-sensitive to me, they'd run on anything. Not sure I'd worry much about improving quench. Then again, they were stockers, never pushed the CR, just drove them. Decent street motors, and not everything needs to make 600HP. They used heavier castings than LA is what I've heard, and metal costs money. Chrysler would do anything to save a buck. It's tempting to think "BBC" when looking at the valve arrangement, but ported Poly heads seem to max out at around 250/200 CFM I/E. Subtract about 50CFM each side for stock. Thanks for the tip, just ordered the booklet. "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: 6PakBee] #2977682 10/23/21 06:37 PM 10/23/21 06:37 PM
Joined: Jan 2003 Posts: 43,522 Round Lake Beach, Illinoisy Rhinodart Rhinotruck
Rhinodart Rhinotruck Joined: Jan 2003 Posts: 43,522 Round Lake Beach, Illinoisy	I just picked up a low mile 66 318 poly and 727 trans, my first ride was a 66 Satellite with a poly and I was always intrigued with it... The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it. JB Rhinehart, Realist A-Body's RULE!

Re: 318 Poly question [Re: Rhinodart] #2977774 10/24/21 06:21 AM 10/24/21 06:21 AM
Joined: Nov 2020 Posts: 348 Isle of Sheeps Gtxxjon enthusiast
Gtxxjon enthusiast Joined: Nov 2020 Posts: 348 Isle of Sheeps	Huge commitment building a stroker Poly! A few (pre 66) friends have started and baled out, but one fine Moparmate has carried on through 'thick and thin'... Divorce, baliffs, forced to move house and no money for beer and Mopar Mags... Once you begin the POLY Project its for life, not just for Christmas...(10 years and counting) He laughs in the face of WEDGE heads now... But a trip to San Diego to see 'Gary Pavlovich' in person and he was struck dumb, with POLY POWER!!! It was a revelation and Epiphany all in one moment! He couldn't believe how folks has dissed the lowly Poly and how the head design was being used in modern V8 engines... Its like Betamax and VHS, the best product doesn't always win out? Its all about 'supply and demand'... 400 cfm Chev-head, can't be bad... Last edited by Gtxxjon; 10/24/21 06:45 AM. Carpe diem, quam minimum credula postero, thanx Horace! There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...

Re: 318 Poly question [Re: Gtxxjon] #2977864 10/24/21 12:46 PM 10/24/21 12:46 PM
Joined: Sep 2003 Posts: 19,355 north of coder moparx "Butt Crack Bob"
moparx "Butt Crack Bob" Joined: Sep 2003 Posts: 19,355 north of coder	Bruce Toth from down around Emlenton Pa. has been working with poly engines over the last several years, and has had several articles published in Chrysler Power magazine. pretty impressive hp and torque numbers from these engines. they are worthwhile reading if one wants to build a poly. just be aware, these non mainstream engines cost way more than the typical small block chebby, but can be a real surprise to a lot of them if built right !

Re: 318 Poly question [Re: moparx] #2978106 10/25/21 07:54 AM 10/25/21 07:54 AM
Joined: Jan 2003 Posts: 1,335 Oregon E earlymopar pro stock
earlymopar pro stock E Joined: Jan 2003 Posts: 1,335 Oregon	I didn't find the cost of building a poly to be any different than building an LA. The only problems are part availability / fewer options which often forces the builder to get creative on adapting other parts. As usual, it really depends on what the build is.

Re: 318 Poly question [Re: earlymopar] #2979292 10/28/21 03:54 PM 10/28/21 03:54 PM
Joined: Jan 2005 Posts: 12,419 Kalispell Mt. H HotRodDave I Live Here
HotRodDave I Live Here H Joined: Jan 2005 Posts: 12,419 Kalispell Mt.	318 poly head is much better than a 318 2bbl head any day of the week, they flowed more and everything, the engine were just bigger, heavier and more expensive to make, the wedge design was a compromise. Boring away .100 in 8 cylinders took out a lot of weight... I am not causing global warming, I am just trying to hold off a impending Ice Age!

Re: 318 Poly question [Re: HotRodDave] #2979492 10/29/21 07:50 AM 10/29/21 07:50 AM
Joined: Jan 2003 Posts: 1,335 Oregon E earlymopar pro stock
earlymopar pro stock E Joined: Jan 2003 Posts: 1,335 Oregon	Agreed on all points Dave. A comparison of the Poly head to the current generation Hemi head underscores the Poly head design is sound. They called the Poly a "semi-hemi" for a reason.

Re: 318 Poly question [Re: earlymopar] #2979525 10/29/21 09:53 AM 10/29/21 09:53 AM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	Thanks to topside for the tip about Victory Library's "Chrysler Poly Performance". I ordered a copy and it is an excellent read. Going through it the only problem I foresee is getting a hydraulic roller camshaft. Everything else seems to be doable....at least at this point. "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: 6PakBee] #2979818 10/30/21 09:31 AM 10/30/21 09:31 AM
Joined: Jan 2003 Posts: 10,704 North Dakota 6PakBee OP I Live Here
6PakBee OP I Live Here Joined: Jan 2003 Posts: 10,704 North Dakota	Have read the entire "Poly Performance" booklet over three times and there is one dimension I can't find. Is the center-center lifter bore spacing for a cylinder the same for the 318 poly as it is for an LA engine? Thanks! "We live in a time when intelligent people are being silenced so that stupid people won't be offended".

Re: 318 Poly question [Re: 6PakBee] #2979849 10/30/21 11:25 AM 10/30/21 11:25 AM
Joined: May 2003 Posts: 6,560 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,560 Downtown Roebuck Ont	Originally Posted by 6PakBee Have read the entire "Poly Performance" booklet over three times and there is one dimension I can't find. Is the center-center lifter bore spacing for a cylinder the same for the 318 poly as it is for an LA engine? Thanks! Yes. The reason the push rod angle for an LA is less than ideal is because the lifter location and angle was not changed. A Poly head can be run on an LA block with some minor modifications, external oil drains from the heads and pushrod clearancing the block. Kevin

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