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gen1dak
Dodge Dakota
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4/20/2005
22:39:23
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 Subject: RE: pre mag mods
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The mods for roller cam were minimal on the pre-mag block, focusing on adding the "spider" that holds the roller lifter yokes in place. This was a good thing, because there were no performance roller cams back then, unless it was a custom grind, and most of the local dirt-tracks wouldn't allow roller cams anyway, so the flat tappet cam swap had to be easy. (Magnums have longer lifters, and the lifter bores are cast deeper in the block, so a retrofit on them is more of a hassle). Ditch the spider and yokes (box 'em up, never know when they might be needed later), they won't be needed with the flat tappets. Slip the flat tappet cam in, use standard non-roller tappets for the "A" engine, and the matching pushrods. The non-roller pushrods (7 31/64")are slightly longer than roller units (6 49/64").
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gen1dak
Dodge Dakota
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4/21/2005
11:05:45
| RE: pre mag mods
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Ooops, I mis-quoted. The rollers gave an 8% improvement, not 4%.
Also, if you're scrounging for 360 heads, look for the last of the line, late 80's-early 90's 360's with "308" in the casting number. On 318's, look for "302".
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Zac
Dodge Dakota
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4/21/2005
11:56:45
| RE: pre mag mods
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Okay thanks. I was going to ask you about the casting number. I knew about the "302" for 318's but i didnt know what the 360 version was. Also is there any difference in the block for the LA 318's? I am looking for another already rebuilt engine to drop in instead of rebuilding mine right now.
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gen1dak
Dodge Dakota
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4/21/2005
14:09:08
| RE: pre mag mods
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The block remained virtually unchanged throughout the LA production. The only real difference pertains to the holes tapped in the lifter valley to bolt down the "spider" for holding the roller lifter yokes in place. The lifter bores on the roller engines are cut down on one side to clear the lifter yokes. This is not part of the bore that the lifter actually rides against....doesn't affect lifter function.
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Zac
Dodge Dakota
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4/21/2005
19:27:46
| RE: pre mag mods
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okay thats good. I found a few mid eighties rebuilt engines that i might get. I dont have many other questions for you right now but if i think of any I will post them. Thanks for all of your help.
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Zac
Dodge Dakota
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4/21/2005
23:15:19
| RE: pre mag mods
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I thought of one more. Will My rearend and tranny hold up to that much power and abuse? Would a shift kit as well as 4.10 gears and a locker help out?
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gen1dak
Dodge Dakota
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4/22/2005
17:41:42
| RE: pre mag mods
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Nope. Any healthy engine should have a well-built tranny. Mopar started putting A518-based trannys behind even the 318 in the early 90's. An over-the-top supercharged 318 with killer boost will definitely need a serious tranny like the ones these guys sell...
http://www.transmissioncenter.net/dodge.htm
The 8 1/4 rear will handle a 300hp smallblock, with some sort of limited slip (or locker), as long as it's for street duty. Slicks or serious big tires, I wouldn't hold my breath. Better to upgrade to the 8 3/4 or 9 1/4. Gears won't help the rear last.
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Zac
Dodge Dakota
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4/22/2005
20:22:06
| RE: pre mag mods
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Would it be possible to retrofit a 727? Or would it be better to find a 518 and put it in? What were the cars that used the 8.75 rearend and what bolt pattern did they have? Will the 9.25 just bolt in? What is the maximum width tire/rim combo I could run in the back before they hit the frame or springs? I am not worried about the wheel wells. I can tub them if i have to.
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gen1dak
Dodge Dakota
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4/22/2005
22:11:59
| RE: pre mag mods
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You could retrofit a 727, but if you plan on driving much, overdrive is a welcome addition. The 727 would require a slightly longer driveshaft. The cost of a well-built 727, plus getting the driveshaft, while still a fair amount less than a comparably built 518, will cost you in gas and engine wear.
The 8 3/4 first appeared in 1957, and ran through around 1974. There were changes along the way, but all diffs are interchangeable. It was used in pretty much all the heavier vehicles, trucks included. It's easily recognized by the perfectly round rear....that doesn't come off like the 8 1/4 and 9 1/4. Instead, the whole "pig" unbolts on the front side. The whole deal pops out. An accomplished mechanic can swap a pig in 45 minutes. Many occasional drag racers would drive to the track with 2.76 gears, pop the pig, and swap in the 4.10 or 4.56 equipped pig, race, then reverse the deal for the drive home. The 8 3/4 has outboard bearings that are greased, while the "corporate" rears (8 1/4, 9 1/4) lube their outer bearings with lube oil from the differential. They used the 5-lug pattern, same size as all the full-size stuff through the 80's. This is where the 9 1/4 may earn the nod. It's still in production, and while the 8 3/4 has a decent aftermarket following, the 9 1/4 is getting more respect lately. You can find it in Durangos and Dakotas now. Swap out the shafts from an earlier model, and you have a 5-lug pattern. As for bolting it in, I don't have specifics on this, but it shouldn't be much trouble. It'll certainly fit. Just not sure how much change there has been to the Dakota mounting points over the years. Max tire/wheel sizes? Well, as an example, I've had 15x8.5 on my '89 with 275/60/15's in the rear with tons of clearance. They did stick out just beyond the fender flares (perfect backspacing on a '69 Charger, but need another inch for the Dak), but were nowhere near the fender itself as far as vertical clearance goes. A 10-incher (with matching tire) should have no clearance issues as far as width is concerned, just so you get the right backspacing.
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gen1dak
Dodge Dakota
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4/22/2005
22:25:23
| RE: pre mag mods
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You could retrofit a 727, but if you plan on driving much, overdrive is a welcome addition. The 727 would require a slightly longer driveshaft. The cost of a well-built 727, plus getting the driveshaft, while still a fair amount less than a comparably built 518, will cost you in gas and engine wear.
The 8 3/4 first appeared in 1957, and ran through around 1974. There were changes along the way, but all diffs are interchangeable. It was used in pretty much all the heavier vehicles, trucks included. It's easily recognized by the perfectly round rear....that doesn't come off like the 8 1/4 and 9 1/4. Instead, the whole "pig" unbolts on the front side. The whole deal pops out. An accomplished mechanic can swap a pig in 45 minutes. Many occasional drag racers would drive to the track with 2.76 gears, pop the pig, and swap in the 4.10 or 4.56 equipped pig, race, then reverse the deal for the drive home. The 8 3/4 has outboard bearings that are greased, while the "corporate" rears (8 1/4, 9 1/4) lube their outer bearings with lube oil from the differential. They used the 5-lug pattern, same size as all the full-size stuff through the 80's. This is where the 9 1/4 may earn the nod. It's still in production, and while the 8 3/4 has a decent aftermarket following, the 9 1/4 is getting more respect lately. You can find it in Durangos and Dakotas now. Swap out the shafts from an earlier model, and you have a 5-lug pattern. As for bolting it in, I don't have specifics on this, but it shouldn't be much trouble. It'll certainly fit. Just not sure how much change there has been to the Dakota mounting points over the years. Max tire/wheel sizes? Well, as an example, I've had 15x8.5 on my '89 with 275/60/15's in the rear with tons of clearance. They did stick out just beyond the fender flares (perfect backspacing on a '69 Charger, but need another inch for the Dak), but were nowhere near the fender itself as far as vertical clearance goes. A 10-incher (with matching tire) should have no clearance issues as far as width is concerned, just so you get the right backspacing.
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Zac
Dodge Dakota
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4/22/2005
23:29:43
| RE: pre mag mods
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The 8 3/4 has a 5 x ? what bolt pattern? also what is the bolt pattern for five-lug gen I daks? If they are the same i could swap out my front rotors for the Gen I versions and then have 5 lugs front and rear.
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vern
Dodge Dakota
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4/23/2005
08:06:31
| RE: pre mag mods
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the 8 3/4 rears are the same as the genI daks bolt pattern 4 1/2" or 4 1/4" center to cnter stud
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Mike S.
Dodge Dakota
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4/23/2005
10:40:27
| RE: pre mag mods
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The lug pattern is 5 x 4 1/2. The largest wheel tire combo that will fit is a 15 x 10 with a 7 inch backspace, That's what's on my 91 with a 28x11.5 slick. I had a Ford 9 inch Narrowed to the stock 8 1/4's specs. Also, I had my A500 built by Bilbrey Racing transmissions in Louisville, KY the internals are pretty much the same as a 904 so there are plenty of racing parts available. 500hp is about the limit that these transmissions will hold up too no matter how they are built. SMR Trans also sells complete A500's and A518's though they are pricy. I have over 40 1/8th mile runs on my tranny and seems just as good as the first. That's behind a 390 with a 125 shot.
Mike S.
91CC Carbed 390 w/nitrous
7.41 @ 94.56 (new) best 1/8th mile
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Zac
Dodge Dakota
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4/23/2005
12:44:08
| RE: pre mag mods
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hey mike what HP are you at w/o nitrous?
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gen1dak
Dodge Dakota
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4/23/2005
15:14:48
| RE: pre mag mods
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No doubt the A500 can be built. There are 904's behind Hemis running 9 seconds in Super Stock. The question is, do you want to spend that much money on it when it isn't necessary? Or will it be necessary? Just what will the truck be? Ultimately, the A518 will be able to handle more than the 500, so it depends on just how much you're going for. Equally built, the 500 will deliver about a 1/4 second quicker time on the 1/4 mile (than the 518) because it has smaller internals that weigh less, meaning less hp loss.
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Mike S.
Dodge Dakota
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4/23/2005
16:47:31
| RE: pre mag mods
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I've never had the truck dynoed so I can only go by what info I have. I bought my stroker kit and heads from Hughes engines. They told my I should be making around 450hp. I run the 125 shot but with 10 degrees of timing retard. On race gas I should be able too run that 125 with no timing retard at all. So I'm guessing it's making right around 500hp. I'm pretty happy with the performance right now so I won't be trying to step it up anytime soon. Plus it's been really easy on parts so I'm gonna keep it right where it is for now.
Mike S.
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Zac
Dodge Dakota
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4/24/2005
14:49:46
| RE: pre mag mods
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What vehicles had the 8 3/4 that will fit my dakota? At least width wise. I can weld on new perches but which ones are the closest. How much HP will the A518 handle stock? the 727? I dont think I am going to go supercharged. I would like to but i dont think i will be able to afford it.
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Zac
Dodge Dakota
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4/24/2005
15:24:40
| RE: pre mag mods
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I was also wondering about hood clearance. Will the edelbrock RPM AirGap intake and Edelbrock Thunder Series 800 cfm AVS carb fit under my hood with the stock air cleaner? I would just like to know so i dont have any surprises when i do the swap. I was thinking about a bolt on scoop from AAR and then just cut a hole in my hood. Which scoops would fit the Dakota hood well?
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Mike S.
Dodge Dakota
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4/24/2005
19:02:44
| RE: pre mag mods
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The Edelbrock RPM Air-Gap and Might Demon 850 fits under my AAR R/T hood with no problems, with a 14" air cleaner on it. I would say with a slightly thinner filter element, mine is 3" maybe a 2" it should fit under the stock hood. I would say a A-518 or 727 should be able too handle around 400hp stock. I have been reading back in this post and I have heard it mentioned that you were thinking of putting a flat tappet cam (non-roller) in a 91 Dakota. Is this correct? If so there will be a fitment problem with the timing cover due too the snout on the flat tappet cam being longer. This will require either use of a older style timing cover (from a carbed engine) or some machine work on the inside of the timing cover. Just thought I'd mention that because I didn't see it talked about.
Mike S.
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Zac
Dodge Dakota
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4/24/2005
19:08:52
| RE: pre mag mods
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Okay thanks. I am thinking of building a carb'd engine building it how i wanted and then dropping it in. My engine is about to go. I can feel it. For the trannies are you talking stock or built? I am trying to do a budget build here. Also will there be any issues with the 727 mounting up or working with everything else on my truck? Does the computer control the shift points and such? Also when I carb it will I be able to go past my speed limiter?
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