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Small block aluminum heads
Does anyone know the pros or cons about putting either the Edelbrock or Mopar aluminum heads on a 74' 318 block.
Also, the reason I'm wanting to put these on are I was told that I'm having issues with a Edelbrock performer intake working with my stock heads because of port mismatching. i was told a good thing a person can do is put the Magnum heads on my block. But I got to thinking and I would have to get new valve covers, headers and make minor valve-train adjustment to make them work. So why not put something lighter on and everything would bolt right up. Anyone know what these would do to compression on a completely stock block and pistons? Summit racing and Jegs didn't know. If anyone has tried these or has any suggestions I'd appreciate it. |
#2
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If this is a street car, why not simply port match the heads you have. It's a ton less costly. Even if you had to buy a compressor, a die grinder and the bits!
I haven't done it in years (decades), but as I recall you can get the port specs from the old Direct Connection Bulletins. Probably find those on line. Just my 2¢. |
#3
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I thought the performance gains would be worth the money of going to the aluminum ones, plus I don't want to mess with the original heads.
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#4
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The edelbrock manifold should match up. Since it doesn't, I think the manifold might have been milled, which often has to be done when heads are milled.
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#5
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Ports on the heads are much smaller than the ports on the intake. Machine shop suggested to "not" mess with the factory heads being 1. they are original 2. they are from 1974 so you can get something much better.
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#6
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That Performer has ports that match 340-360 heads, which have taller intake ports and bigger valves. These heads bolt on to a 318 but you'll lose compression on some smog heads.. Get a junkyard set, have them milled for cleanup do a basic valve job and try them. You'll still have your original ones. Ideally, find the last LA truck 318 head, casting # ends in 302. It outflows all the previous castings, you won't lose any compression, but you might still need to deal with port match - not sure. Any throttle-body injected 318 pick-up or B-van will have these heads. (Magnum heads are another story - they are not a "bolt-on")
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#8
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You're welcome. Couple of cautions here - have your " new" heads checked by a reputable shop for valve seat cracks and coolant chamber cracks. In other words, Magnaflux and pressure test them. Also check the surface for flatness, and mill or surface-grind as needed in order to get the flattest surface possible. It'll cost a few bucks, but you will know they are solid (or not) before they go on the engine. You can do a minor valve job yourself if (when) they check out.
According to the info I have, the TBI engines that these heads were on used roller cams and had shorter pushrods. I don't know whether your stock flat-tappet pushrods will interchange. I'm thinking they shoud, but check that out as well. We need someone here who has done the swap for more info. |
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#10
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According to the info I have, the TBI engines that these heads were on used roller cams and had shorter pushrods. I don't know whether your stock flat-tappet pushrods will interchange. I'm thinking they shoud, but check that out as well. We need someone here who has done the swap for more info.[/QUOTE]
I was going to write you back and ask you about that. I was doing more research yesterday and also talking to my machine shop about the heads. The guy there asked if I knew that that was a roller head and at that time it didn't know it was. He said it can work but he wouldn't put that head on his engine. He suggested putting a tad bit higher compression piston in and getting a different set of heads. What heads I don't know, he just suggested something different. Will my rocker arm shaft and rockers work off of my stock heads? The place selling the head nor the machine shop knew for sure. Thanks again. |
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General Opinion
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#12
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[/QUOTE] The guy there asked if I knew that that was a roller head and at that time it didn't know it was. He said it can work but he wouldn't put that head on his engine. He suggested putting a tad bit higher compression piston in and getting a different set of heads. What heads I don't know, he just suggested something different. Will my rocker arm shaft and rockers work off of my stock heads? The place selling the head nor the machine shop knew for sure. Thanks again.[/QUOTE]
If he doesn't know of a better head but wouldn't use the '302, I'd get another machine shop. I don't know what he meant when he called it a "roller" head, as 340 said, TBI lifters were roller-type, and therefore taller than the flat-tappet ones. The shaft rocker system is the same as the older heads, and the last LA head to use them before the Magnums with their stud-mount rockers. So sure you can use the shaft and rockers that you already have. Pushrods are a different matter, but only getting the correct length. A checking pushrod is available and inexpensive, and you might have to go that route if your old flat-tappet rods won't fit. The order a custom set once you've established the length you need. Hughes Engines seems to have a pretty knowledgeable website for this sort of info, as does Rick Ehrenberg at Mopar Action mag. |
#13
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In stock form the 302 heads are not that good. Installing 360's 1.88 intake valves' opening the bowl and the pushrod pinch that is heavily shrouded by the big pushrod hole required by the roller lifters, and porting the exhaust bowl & port makes them a really good head for a street 318. http://www.shadydellspeedshop.com/302.htm
A stock performer intake should match 318 heads intake ports, and is also a good match otherwise up to about 300 hp. |
#14
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302's are also found in Dippys, New Yorkers etc.
They will wake up a 318. |
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Yeah I forgot about them - 85 or 86 and up used the '302 and roller cam, but were still carbureted engines. DartGT66 has a point regarding the small (1.78") intake valve, but that can be machined to use the 1.88" (360) valve. I wasn't aware of the port obstruction he mentioned. I assumed the Edelbrock manifold involved was a Performer RPM or Airgap, I knew the stock Performer has the small ports and essentially is a copy of the iron stock unit. See why we need someone who's done the swap?
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#16
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Quote:
I already have @ 7:5:1 compression, by putting on the 302 heads it will make things the same if not worse. If I add taller pistons to bring the comp up I'll have issues with the heads and then I'll have to mill the block & heads, port match the heads with the intake. The machine shop said ill be into them for a lot of $. I'm not looking for 400hp but I want a little get up and go. That year 318 just sucks for making performance upgrades is what I've been told. Been told just get a 360 and be done with it. Engine builder told me I'd be better off just putting in my 3:55 gears, put back in stock cam and put the 2 barrel carb back on. He thinks that combo would trump what I've already done. |
#17
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Well, that approach is certainly the easiest way to go! I was under the assumption you wanted to stay with the 318. I have heard conflicting stories about "crate engines" so be cautious when you select a vendor. I'd be looking at a stroker 360 (408 cu. in.) if it was me, from somebody like Hughes Engines, Indy, Ray Barton, or other Mopar shops. I still think your machine shop is mis-informed about your 74 motor, but that's just my opinion.
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#18
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You ever heard about CME engines? They have a 360 375hp for $3600 or a 408 400hp for $4000. They offer warranties on these for 2 years. Thanks again. Jeff |
#19
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Hi,
I've had very good results with the 302 heads on a 318. Had a stock set on my dart that pulled 212 RwHp and 249 FtLb on a conservitively operated Super Flow chassis dyno with headers and a mild cam (0.419" & 220@0.050") with 9.1:1 compression. Had a set ported by Ryan Johnson at Shady Dell in PA. With 1.94"/1.6" valves they pulled 250 RwHp & 284 FtLb with 9.5:1 compression (same cam with Hughes roller rockers). A couple of years later we milled the heads 0.030" and switched in a mech roller cam (0.600"& 260@0.050") and got 330 RwHp & 303 FtLb (all on the same chassis dyno with the same operator). Intake has been an Edlebrock LD4B with a 750 Mech 2ndry carb all along. The 302 is a good head, it'll bolt on, uses all the same valve train stuff for the LA engine they're going on (this whole roller vs flat tappet thing is nonsense, pushrods are always going to go with your cam & lifters, so your current pushrods & rockers should work fine). They are still small port heads though. So lets be clear about what intakes go with which heads. The Edlebrock Performer and LD4B are small port intakes that match well with 273 (yeah I know about the whole head bolt angle thing, that's what a rat tail file and hardend washers are for) and 318 heads, the Performer RPM, LD340, and Performer RPM Air Gap all work with the larger ports of the 340, 360, and Edlebrock heads. For my money on a street 318 I'd go with the LD4B or Performer intake with the 302 heads. One major plus of the 302 head is that it has the smallest (nominal) combustion chamber of any of the small port heads since the old 273 castings were phased out in '68 or so. So it's likely they will raise the compression of a smog era 318 without the need for a lot of milling. Dave |
#20
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I have not heard of CME Engines, but hey, I live out here in the boonies If they're a relatively local shop, get some references. Prices don't sound too bad but just be sure to get as much info as you can about what's included, etc. Good example in my own case, when I had my 360 rebuilt, I picked a reputable shop owned by a guy who held an NHRA class record at the time. Trouble turned up 7 years later, when I found out he'd farmed out the crank balance job to a shop that didn't know how to do a 360 externally-balanced crank. So get all the info you can. It would probably help if you posted more detail on the area you live in, more members could recommend shops in your area. |
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Here are some flow numbers I've collected over the past ten years:
STOCK 302 1.78"/1.5" (Shady Dell) 0.100" 62.8 NA 0.200" 125.6 70.9 0.300" 158.4 92.8 0.400" 169.3 99.6 0.450" 170.6 101.0 0.500" 170.6 102.4 0.550" 170.6 102.4 0.600" 170.6 102.4 As Cast "302" 1.78"/1.50" (Dart/MPC) 0.100” 51.8 36.5 0.200” 92.5 70.7 0.300” 130.1 104.3 0.400” 163.9 113.2 0.450” 169.1 115.2 0.500” 170.4 117.3 0.550” 172.2 119.0 0.600” 172.5 120.4 "J" 2.02"/1.60" (Shady Dell) 0.100” 62.1 46.6 0.200” 112.1 99.4 0.300” 156.6 128.3 0.400” 193.2 137.3 0.450” 200.1 138.3 0.500” 200.1 139.7 0.550” 200.1 140.8 0.600” 200.8 141.5 Ported (Shady Dell) "302" 2.02"/1.60" 0.100” 71.8 42.5 0.200” 148.4 86.3 0.300” 212.2 113.9 0.400” 241.5 131.1 0.450” 244.6 137.7 0.500” 246.7 139.7 0.550” 242.6 144.9 0.600” 240.8 144.9 Ported (Shady Dell, Heads on the Dart Prelminary) "302" 1.94"/1.60" 0.100” 68.8 47.5 0.200” 138.4 110.3 0.300” 202.2 130.9 0.400” 221.5 141.1 0.450” 230.6 157.7 0.500” 234.7 170.7 0.525" 238.0 175.0 0.550” 236.6 170.9 0.600” 236.8 171.9 Ported "302" 1.94"/1.60" Actual Numbers Final intake port volume: 136 cc Shady Dell | MPC 1 | MPC 2 LIFT IN / EX | IN / EX | IN / EX 0.100" 66.1 / NA | 63.6 / 48.4 | 65.7 / 49.6 0.200" 132.8 / 90.4 | 126.0 / 95.8 | 128.6 / 94.5 0.300" 189.9 / 126.2 | 175.3 / 131.9 | 174.7 / 130.6 0.400" 218.4 / 148.8 | 210.4 / 155.3 | 208.6 / 157.5 0.450" 227.9 / 152.9 | 218.1 / 161.9 | 216.6 / 166.0 0.500" 232.8 / 159.8 | 199.5 / 165.7 | 205.7 / 171.1 0.550" 238.0 / 163.9 | 200.1 / 167.6 | 203.0 / 173.3 0.600" 239.1 / 169.8 | | "J" 2.04"/1.625" 0.100” 62.1 51.8 0.200” 135.2 103.5 0.300” 198.7 135.2 0.400” 239.8 158.7 0.450” 253.9 169.7 0.500” 258.4 182.9 0.550” 264.9 186.3 0.600” 254.6 186.3 273 Ported 1.88"/1.60" Maryland Performance Center (MPC) 0.100" 60.93 48.78 0.200" 122.75 99.78 0.300" 179.68 137.16 0.400" 197.02 157.11 0.500" 185.91 168.20 0.600" 187.24 179.29 273 Cleanup Port/Valve Job 1.78"/1.50" Maryland Performance Center 0.100" 49 43 0.200" 98 85 0.250" 124 100 0.300" 145 112 0.350" 162 120 0.400" 179 125 0.450" 188 129 0.500" 190 132 0.550" 185 134 0.600" 177 135 |
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