Anybody got any clue how much you can resurface the heads on a 270 Dodge hemi?? I cannot locate an answer anyplace. That is all.
As much as possible. Back up for the daytime guys...somebody has gotta know without me calling Bob, he's a busy guy.
You can whack 'em alot.I don't really know what the end of the road is though. Is it a solid or hydro cam? Adjustable rockers are nice but rare for those little motors and adjustable pushrods are a mojor PIA to adjust. What are ya tryin' ta do?
Thank for the reply. I shall not attempt to take the high road...I'm looking for a little more compression without buying pistons. The engine I'm working up has about 35K miles on it (no kidding) and has virtually zero wear on the bores or piston skirts. I kinda hate to spend the money on Ross or similar slugs when the stockers are in such good shape. Not trying to be a cheapass really, but it's *almost* a needless expense. I realize I'm not gonna magically end up at 10.0:1 by cuttign the heads, but anything has gotta be better than the factory 7.6:1. BTW, I'm using a hyro cam, so hopefully the pushrods will be a set and forget deal. I'd run a solid, but like you said, adjustable rockers ain't falling out of trees.
I can't recall off the top of my head what the stock combustion chamber CC's are,but....considering the small bore and stroke of these engines....even using a headsaver shim instead of a "head gasket" and milling the crap outta the head and decking the block still won't make much improvement in the CR. Pistons unfortunately are the only real solution to getting a respectable CR outta these engines.
Hello..The 241..270 have low compression, run a blower..What a great match. Rocker Arm Specialties..might have a set of adjustable rockers.. Duane.
There's a guy here at the swap meet that has a set of covers for a measley $350 bucks.No Rockers though.LOL You can make your own with a ball peen hammer and a peice of steel with a hole in it. Blower manifolds for a 270 are for all practical puposes non existant for these engines and the physical size limits them to a 471 which is okay since that's about all they'd want anyway. If you wanna huff it you gotta make your own manifold, or get a genie to come up with one. Walker was threatining to start makin 'em but the price was gonna be way stupid.
Milling the heads to drastically increase CR will put the engine's geometry way outta whack by the time you finally get there. With less than 8:1, I would seriously look at forced induction. The HAMB'r known as SHIFTS has a Model A with a 4-71 blown Dodge HEMI in it. Here's a couple threads you'll probably find interesting: http://www.jalopyjournal.com/forum/showthread.php?t=101680&showall=1 http://www.jalopyjournal.com/forum/showthread.php?t=110419&showall=1
Actually, with corret length pushrods there is no geometry change with reduction in head height. Blower is not an option here.....I'll do more math on the CR issue with stock pistons and less chamber, if not I'll bite the bullet and order a set of Rosses. Thanks for the replys guys
You're right about the push rod thing. You don't need to waste the time on the math.I've been there,done that,I just cant recall the #'s now and I don't think I saved the notes. but here's a pic of the lump.
Your lucky in having a Dodge hemi...I have a Desotto hemi, which in turn is almost double the cost in making parts to fit. I have found several pistons that can work with these older builds. The worst problem is the connecting rods and piston matching. The older cranks and cams are very valuable. Meaning rare and near impossible to find. If you need to increase the HP without spending a great deal of green stuff.......you need to inspect your piston design and find pistons to match. I am working on a total over bore and SS sleaving for the new build. And I don't really know if your cam is has the tapper bearings, but I would prefere to have a line bore done for the input of a newer type engineered cam layout. The cost in building my hemi is going to be well over $5K for the old beast....but, when finished, it will be a very pricey prize if anyone might be interested. As far as your base plate for the blower, you will need to make one. There are a couple routes you can take, both will be worth the money in the long run. A simple base plate will cost nearly $700.00 to be machined out of the new aluminum alloys available. My old intake weighs in at 50lbs or better. You can always build one up out of SS and add a ram jet style TB injection unit like the mustang uses. Or you could add injecter bungs to your old manifold and go exotic with multi-port-injection along with a medium sized turbo. Or better of two T4 trubos, one on each side would be a more managable system for the 270ci. There are plenty of Durangos' in the local scrap yards, which should make it a possibility to scroung there computer managment system and addapt it to your now MPFI hemi. Any way you look at it, for a quick increase in the HP of that pocket hemi, your most quickest improovment, is to get a Vortec Belt driven SuperCharger. You will need to have the heads done over, you know, harden seats and new valve guides, spring seats, studs, the whole works. My heads are running $500.00 for the complete upgrade, and that is with larger valves and the latest flow test cutting available. Hemi engines are very expensive, and be thankful you have a Dodge and not the Desotto hemi. Good luck....built your intake and don't be bashfull of going to the extremes with your hemi.......you have one and everyone wants one....lol......... Maximo
I wasn't talking about valvetrain geometry... I meant intake manifold ( and water crossover, too if being used) alignment. Give me the piston height (above or below deck @ TDC) and head volume cc's and I can calculate it for you - I made a computer spreadsheet to do the math for me.
Oh. No worries there, the intake will be fabricated after the fact. No worries there either, I used Google to find a spreadsheet to do the math for me about 5 years ago
That's sexy. Since it looks like I'm gonna just buy some pistons, let's be off topic...what are you doing for a water pump? HH adapters? I am making a plate style front mount with the adapters built into it. It'll pick up all the timing cover bolts, and I'm thinning a stock cover down to fit over the plate. What water crossover is that? And as ricardo said, I guess that's a 315?
Remember, you're going for a traditional look, and performance be damned. I think 200 HP is probably about all you are going to get out of it and maintain reliability. If you want more HP than that, then trade-up to a Chrysler hemi.
It's a 270. HH adapters to bbc short pump.They're real thick though,I don't believe a motor plate will get you there from here.Mostly because of the difference in C-C between water pump and block. Water crossover is modified stock,Cut loose from the rest of the crap with the hole in the bottom welded up.
I'm a student of the 270, so it's interesting that yours has motor mounts. I heard that 56 blocks had motor mounts, but I have never seen one. Then I heard that the 56 270 poly blocks were actually the ones with the mounts, and people put the hemi heads on it. Is yours stamped as a D553? Thanks
I have a '55 Super Red Ram 270" engine and a shop manual for it that lists the stock compression ratio at 7.6 to 1. From a couple of obscure old magazines I found some info about milling the heads. In a 1956 Popular Mechanics Hot Rod Handbook in an article entitled " How to Hop Up Production Engines" for the Dodge and DeSoto hemis they say that .050" maximum can be milled from the heads without creating detonation problems. And in the November 1957 issue of Speed Mechanics in an article written by Roger Huntington about the Chrysler family of hemis in general he states " About .060" is as much as you should try milling the heads. This .060" mill will raise compression ratio an average of one point on these engines." Anybody know anything about the 270's having a problem with their lower ends? This was possibly a problem with '55's only. I found one article about the '56 D500 with a 315 cubic inch hemi where they mention that Dodge by that time had solved their crankshaft problems. And another article from 1957 about sstock engines recommends avoiding the '55 Dodge 270" engine for racing or hot rod use due to the same problem.
Greetings to All. Considering what is desired as an end result, it sounds like you will waste time and energy (and probably parts) trying to get around the need for forged pistons. Buy the good stuff, put in a cam to match and drive it like you stole it.
I know this is an old post but I ran a 241 that had the heads cut .060 because they reduced the base circle that much when they reground the cam and I don't like adjustable push rods that much ran a fabricated manifold and chevy water pump
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