Anyone have or know anyone that has High performance parts for a 258 AMC 6 banger, Working on a stock car with a 258 inline 6 cylinder... I know there must be some aftermarket goodies out here... Thanks racinman Rick
Thanks guys We are building a rambler into a dirt track race car... for the 6 cyl class. just need as much help on the go fast goodies. and internal parts... racinman Rick
Clifford is there, but pricey. What are the rules? The internal parts are good for 6000 rpm, but you're better off to capitalize on the low end grunt rather than rev the hell out of it. Use a towing/4 wheelin' cam with as much low speed grunt as you can get -- something that tops out at no more than 5000 rpm. Isky makes a few. If you can use a later model head get a 96-99 (casting #0630) head. The ports are smaller than the 91-95 7120 casting which most web sites say are "the best", but there is literally NO FLOW DIFFERENCE between the two. The 96-99 has very clean cast ports, the 91-95 ports need a lot of pocket porting work. With the 4.0L head you can use the factory 91-98 tubular header or get something like a Borla (there is very little, if any, difference between the 91+ factory and any aftermarket header in flow, save your money!!). ANY 4.0L head will out flow the older 258 heads. You MUST use the 4.0L exhaust and valve cover, but the 258 intake adapts easily. What about carbs and intakes? For street and wheelin' I always recommend the Offy Dual Plane. Keeps charge velocity up during low rpm operation. You might benefit from that on the dirt track, at least during take-off. But an open plenum intake will probably work just as well, maybe better. I'd use a 500 cfm Holley 2300 or a 600 cfm 4V carb. For street I recommend a 450-500 cfm carb (the little Holley 390 for gas mileage and a bit of power). Anything over 500 cfm is usually a waste, but for all out racing some of the guys have had good luck with 600 cfm carbs, and they are much cheaper than smaller ones. It all depends on how you build. The smaller ones work better at low rpm, the 600 works better for high rpm (3000-5000). There is a harmonic vibration in all six cylinders at some point. The longer the stroke the lower the rpm. For the AMC sixes it's somewhere in the 6000-6500 rpm range. You can run right up to that point and even through it, just don't run AT it. The point is only like 50-100 rpm "wide". If you start getting engine vibration at say 6150 rpm, it will be gone if you just get up to 6200-6250. Run between 6150 and 6250 for long and you'll beat out the bearings and possibly break a crank. The exact point varies with engine stroke and balance. No need to balance the six cranks -- they are inherently balanced by design (one good of the good things about the I-6 design!). Just match weigh the pistons and rods ends and you're done.
How far do you want to go with this? Can you run a 4.0L block? If so I have a few tried and true stroker motors we build out of them for out comp. Jeep CJ's. Keith
Swap a late 4.0 head onto the 258, 50 easy horses. Google 4.0 Jeep head on a 258, there are several sites with all details. I ran an Offy Dual Port with a 390 cfm Holley on mine with a Crane 260-2NC cam, really ran strong.
Like Farms said, build a stroker. Drop that crank in a 4.0 block, and then you have the good head too. H.O. heads are even better. 275 hp and 300+ ft/lbs should be very doable with mild compression and mild cam. Makes for good fun in a light vehicle. Offenhauser also makes intakes if your too cheap for the Clifford stuff.
F.O.G. -- that's a fallacy that has been spread over the Internet. The head alone won't add an appreciable amount of power. Might add 10-15 hp at the most. Been there, done that. Now if you add the head along with the EFI system you will gain about 40 hp. Note that you're changing the exhaust manifold whenever you change the head as the 258 exhaust won't work -- the center exhaust ports changed from siamesed to individual ports. So you can't change the head alone, you're adding a header as well. The engine REALLY needs a better cam when adding EFI. It will work with the stock carb cam, but the stock 4.0L EFI cam is an improvement, even if you keep a carb. If you have to run a stock AMC six cam that's the best one to use. I have a Mopar Performance cam in my 4.0L though. The Clifford stuff is expensive. I wouldn't say "to cheap for the Clifford stuff". The offy offerings are just as good on the intake side, and the Dual Port intake is much better for a street vehicle than the Clifford open plenum design (or the Offy open plenum).
Thank you farna!!! I am so sick of people spreading that mis-information. Like the other one of the late model horse shoe EFI intake being good for 20HP. If a stroker is on your mind PM me for more info on head,cam, crank, block options. Keith
I build racing engines, if you want a hot 6, get a good cam, put in some good bearings, have the head ported, deck milled .030, have your block bored, flat-tops, and have your block decked. run some 10:1 pistons, get some headers, and you can build your own intake. 3x2's are fun! 300 Horses easy and with a I-6! Horses are in the breathing....need any more, use a little NOS. Good dependable fun!
Takes me back to the 70s when the State of Wisconsin decided it would be a good idea to buy State Patrol cars from AMC to try to keep them in business. They had a top speed requirement that they couldn't reach. I don't recall if it was 100 or 120. The AMC dealers were looking for aftermarket speed parts for the V-8. A guy at a local speed shop told them they'd have a better chance of finding a fat man that doesn't sweat. Even if speed parts would have been available, Emission regulations wouldn't have allowed them to be installed. I think the State used them for employee transportation and got different patrol cars.
Thanks Guys... We are going to build this 65 Rambler 220 American into this dirt track car... The rules are pretty open and I just love hearing the I-6 sound and can run it without breaking the bank... I will keep you posted with this...
Engineman, that's another stupid myth! Now if they were buying six cylinder cars maybe, but AMC never made a V-8 car that wouldn't hit 100 mph -- I'll even go out on a limb and say 120! The old 250 cubic inch V-8 might have taken a bit of time to get there, but I doubt it (and that was 1956). In the 70s any AMC V-8 in a suitable size car would do the same. A 304 (the smallest AMC V-8 in 1970) in the biggest Ambassador might have had some problems, but so would a 305 Chevy in a Cadillac! A standard 67-69 343 AMC is actually HOTTER than a 327/350 Chevy, except maybe the Corvette version. AMC V-8s have similar output to any other V-8 of equal size. Alabama was the first state to use pony/muscle cars for their highway patrol -- 71 and 72 Javelins with 401s. Fastest cars they ever had, many 140+ mph pursuits. AND THIS IS ALL DOCUMENTED -- http://www.javelinamx.com/javhome/copcar/alabama.htm. Two of the most amazing facts: 1) After two small modifications by ADPS Maintenance (improving oil flow and adding a 1st-gear lock-out), no ADPS Javelin ever blew its engine AND 2) No ADPS Javelin was ever outrun in a pursuit.
Looks like Keith (383 240z) and I have built Jeep 4.0L stroker motors before (or are at least real familiar with the AMC/Jeep six) and can advise you pretty good on them. Ask here or PM one of us!
Been readin all this stuff about 6 cyl inlines and it ranges from , six are sick, V8,s are better, not trad, etc etc. Being that I was a very V8 guy when I was young and doin some street racing with my 56 Chevy powered 31 Model A [in56]. I was rudely made aware of a 270 GMC in a 37 Chevy coupe that grew smaller very quickly one nite. I had an awakening at that time. As far as the Jeep 6 js concerned I was impressed with my son,s 5 speed 86 Cherokee. All I can say about that engine is just that its just a good breathing, 12 port, 7 main bearing, quality engine. Barney Navarro built the AMC version up to 700 hp.So I will use any of the the later 6,s Mopar,GM,Ford even maybe a DOHC Jag, and as long as its a straight 6 in my 39 Chevy, hey whats in a valve cover! and whats so hard in adapting or making a inline intake manifold? Gads a strait 6 inna 39 Chevy whatta concept!
The Ford 240/300 six is good for performance, but the 144/170/200/250 six is hobbled by the intake made onto the head. They never had anything but a 1V carb. There is an expensive Australian made cross-flow head, and you can machine the built-in intake to take another pair of carbs (or block the center one and use two), but that's about it. Best thing to do is put a small turbo on it and force the air in though. The Aussies made a high performance version since big V-8s weren't so much in style down there as here in the states. The Jag six is expensive to rebuild. That's why you see a few V-8 conversions. There's at least one company that still makes conversion kits (for the Jag 6 and V12). You can still buy parts for the 250 Chevy six, but most racers who use an I6 use either the AMC/Jeep 258 or 4.0L or the Ford 300.
Years ago I knew a guy with a 62 Rambler Ambassador sedan with the 327. That thing was ugly but man would it go. Similar power to a 327 Chev but the unibody Ambassador was a lot lighter than an Impala. Likewise the early 70s Ambassador with the 401 4 barrel dual exhaust. What was surprising was, you don't expect a big old AMC sedan to be that fast but they were.
I remember the AMC squads well, with a 401, they weren't slow, that's for sure. I'll bet they would run 130. They weren't as fast as the Plymouth 440s that they replaced, but they had air conditioning and the cops liked that. LOL The slow ones were the Dodge Diplomats with 318s! 110 with the light bar, 115 without, ask me how I know. LOL
I guess you found an old Jeep with the six? Unusual choice for a Swedish hot-rod, though the Saab turbo is understandable!
I bought a Hornet -73 and took the whole drivetrain out of it. Saab and Volvo parts are everywhere. Yes, all my friends uses Chevy V8 in their rods but this one runs very good. I have used it the whole vinter, only changed to studded tyres.
Did you make that body using a 32 or so Ford cowl, or is it something from up that way? It's SMALL!! Couldn't tell how small until the pic with you beside it!
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