69' amx
R/T,
Check out the AMC forum site. The 69' AMX was, I think, was intended for SS/G with a 390/340HP rating. Of course, it did not fly, was properlry re-factored to, I think 405HP. I think they bounced from SS/E, to SS/D to SS/C. The 390/315HP car was classed in SS/J in 69', and/or F/S. Good article about the special 'Crane' heads set up for that engine. PC |
Re: 69' amx
The Crane heads were ported w/ 2.08/1.74 valves and were OEM installed. They were only applicable to the cross-ram 390/340 engine.
As far as I know, they were the only OEM ported cylinder heads. Engine package included the dual 585 cfm Holley's on an Edelbrock STR intake & domed pistons, headers and a dual-point distributor. The 390/315 received standard production car cylinder heads. |
Re: 69' amx
The '69 AMX 390/ 315 has always been a 10.00 factor right at the top of E /S and SS/I.........At one time , the SS AMX engine was the most heavily factored HP in SS , even more than the Hemi's and BB Chevies@75 HP over the rated HP .......Tom
|
Re: 69' amx
The article about the special "Crane" heads for the 69' AMX S/S car,
was that they utilized Mopar 440 valves. The 69' 'Crane' heads were good, but in 1970 the 'dog-leg' design exhaust ports flowed much better, than the flat-style 69' heads. Does that sound correct Jeff. I guess, AMC wanted to utilize the 70 'dog-style heads' for the 69 S/S cars, but could not. They would have to build another (50) 70' AMX S/S cars. Instead they offered 70' front-end conversion kits and replacement trim components and dashboard units. NHRA would not legalize that conversion, due to the fact that the 70' AMX frame had a longer wheelbase than the 69' car. I think thats in the ballpark. Either way, AMC got somewhat screwed. PC |
Re: 69' amx
Wheelbase for 1968 - 1969 - 1970 AMX's are all the same, 97". You may be confused in that the overall length changed a few inches as a result of body overhang. But the wheelbase remains the same on all 2-seat AMX's.
I assume AMC sent out the 1970 sheetmetal, tail lights, dash, seats, etc. (even a 1970 VIN plate!) to the owners of the original 1969 SS/AMX's more because they wanted a new for 1970 product in front of the public. The 1970 production heads are an improvement over 1969 and earlier production heads but in a SS application back then, I believe the 1969 ported Crane heads were better than a 1970 production head (remember, this was back when SS did not allow porting). Note: AMC did not send out new "dog leg" 1970 cylinder heads to the racers, only body change items. The SS/AMX's were fast right off and continued to be so well into the 1970's. Several years ago the dog-leg cylinder head was approved as a superseded part; long after the cylinder head porting rules took affect. The fact is, AMC was the poorest of the auto manufacturers. They could not justify building another 50+ cars (at a loss) in 1970. So they thought they could get around the NHRA mandate that all cars be "assembly line produced" by replacing the relevant parts with full corporate approval. Again, note AMC provided NEW 1970 AMX VIN plates! Clearly, this was the intent of the manufacturer that 1970 AMX SS cars were to be recognized and raced along with 1969 SS/AMX's. But rules are rules and once NHRA saw what was going on (and it wasn't a super-secrete deal either), they put a stop to it and advised all racers that if they wished to race an x-ram AMX then it would be a 1969 model. Numerous owners who made the conversions with AMC's blessings along with new paint jobs, parked the cars in disgust (gee, does anything ever change?). A friend of mine has one of those cars. It was raced in 1969, converted per factory recommendation and subsequently parked. The only good thing is the 1970 VIN plate allowed easy MVD allowance for this once "race only SS package car". The car accumulated 70,000 in street miles before my friend bought it and restored it; back to race day 1970 with 1970 parts still intact. It is #3 of 52 produced. Now, however, an interesting argument could be made to re-instate the 1970 AMX as a x-ram car due to the new "crate motor" cars in S/SS. This was, and no doubt about it, AMC's intentions. |
Re: 69' amx
Jeff,
You couldn't have described those details any better. I always figured, that after the factory cars suprised everyone at the 68' Winternationals, they would not let the factories per say, run the show. ie; (Not 50 produced) 68' Cobra-Jets (not factory-production until April 68) 68' GSS 440 Darts (just who had them in January 68') 340 Cuda's and Darts (factory rated at 275HP) Even the 67' R/O Plymouth's and W/O Dodges (does anyone really believe there were 55 of each produced) They started cracking down, just before the 68' Springnationals. Made Plymouth and Dodge show the sales documents for 50 sales (each) of the factory SS/B Hemi cars. They were made legal about a week before the June event at Englishtown. |
Re: 69' amx
Jeff has it right. ...There is a '69/'70 down near Lancaster ,Pa. .....the owner showed me the documentation.....The later '70/'71 3196291 head casting superceeded the original rectangular port heads, I believe in the mid '80's ..............I have an original, damaged, Crane head . The porting was nothing spectacular by todays standards, but in '69 it was probably better than the best Modified Elim heads ......Tom
|
Re: 69' amx
Maybe you don't know that Crane offered ported & polished cylinder heads in their catalog during this time period. There were two versions of SBC heads that could be purchased for around $500. Many Modified racers ran those heads in the late '60s & early '70s. Crane had a production facility set up to manufacture the heads in quantity so it makes sense that AMC contracted with them for the heads. Very much cheaper than new castings.
|
Re: 69' amx
I knew about the Crane Chevy heads, but didn't realize they were available as early as '69. .....I always thought they were from around the mid '70s. ...I remember the speed shop I delt with getting a set for a twin turbo Don Hardy Vega the owner was building around '75. ........Make you sad to think of the fate of a company like Crane, that pioneered so many things........AMC did make some very special head castings for the NASCAR program. ....I managed to have 2 sets of these over the years,and thy did some things that were not seen on aftermarket heads till many years later. ....The intake floor and roof were raised up substantially , the top of the intake runner was flush with the valve cover rail. ....The decks were about .125 thicker than a production casting. ...the finished set I had came from Traco ,and were angle milled 1.5 deg, giving the head a 16 deg valve angle and a 42cc chamber,and a 230 cc intake [178 stock] in 1974 !! ..........Tom
|
Re: 69' amx
Quote:
68-69 was different from the 70 amx's.. |
Re: 69' amx
Jeff,
Wasn't the issue, that the 70 'dog-leg' exhaust port design flowed better than the 69' exhaust port design, and AMC wanted to get them out there (supposedly an additional 25+ HP) over the 69' heads. And that the 70' heads were to be prepped by Crane (ported and tricked-up). AMC wasn't about to build 50 more 1970 Super/Stockers, so they offered the 70' upgrade kit for the 69 S/S cars, so they could utilize the newer and better flowing Crane-prepped 70' heads. The 70' 'dog-leg' Crane heads would not be legal for the 69 s/s cars, but would be legal for 70' S/S cars Of course, NHRA put the 'kibosh' on the up-grade kit. Paul |
Re: 69' amx
Quote:
The cheap / easy way out for AMC was to just change out the sheetmetal parts and carry over the engine parts. Tom, Yes, the front suspension on the 1970 AMC is substantially different than the 1969 AMC. I know of at least one racer that converted his '69 AMX to a '70 AMX with all the sheetmetal parts and was later advised he had to change his suspension (which he did). |
Re: 69' amx
Jeff,
I thought the cylinder heads were the same casting. Don't the 69' S/S "Crane' heads have slightly larger combustion chambers, due to machining for valve schrouding, and not casting. I think Kaplan Engineering has something discussed about exhaust flow and the major incease in flow developed at higher rpms, with the 'dog-leg' design. Just read my old 68' Drag Performance Mag 1968 AMX 390/315,,E/S With Doug Headers, 4.44 gears, 7' slicks, Schieffer clutch package, and dyno-tuned. 13.07 @ 108mph PC |
Re: 69' amx
The original 1969 SS head was based on the production head, ending with -558 and had rectangular exhaust ports. The standard -558 production head in 1969 shows 49.10 cc chambers while the SS only -558 head shows 57.00 cc chambers. So yes, the chambers were somehow modified on the 1969 SS only head.
1970 production cylinder head started with -291 castings which had the dog-leg exhaust ports and still retained the 49.10 cc chambers. In Stock the 343 is rated at 275 HP and the 390 is rated @ 315 HP. They both look better in SS with 265 and 290 HP ratings. |
Re: 69' amx
The 558 S/S head had the chambers completely opened up to unshroud the larger valves, accounting for much of the increased volume. The heads I had were completely polished , and came from the S/K Performance car . .........Kenny Freeman was instrumental in getting the 558 superceeded by the 291 casting ........AMC by that time could have cared less. ..........Tom
|
Re: 69' amx
I have a SS/AMX owner looking or an original pair of Crane heads for his restoration. Anybody have a good pair (no cracks or ported beyond recognition), let me know!
|
Re: 69' amx
I think I got it.
1969 AMX S/S cars. Engines with 390 Cross-Ram. 69' heads, modified by Crane, ported out, with Mopar 440 valves. Combustion chamber (49 cc) hogged out to (57 cc) to reduce valve schrouding. Cars were running in SS/D for 70', versus the Street Hemi cars (primary competition). Kaplan Engineering discovers more flow and 25+ HP at higher RPM's in the new 70' dog-leg ("L"-shaped exhaust port heads). Approximate gain of 3/10's off the E.T. AMC wants to utilize these heads on the 69' S/S cars as a replacement head. NHRA says "No Way'. Since they are a 70' design, they can only be accepted on a 70' car. AMC, not interested in building an additional 50+ 70' AMX S/S cars Decide to produce 70' up-grade kits for the 69' AMX cars. Front grille, fender extensions, light hardware and dashboard. With the 70' conversion, the newer 70' Crane 'dog-leg' heads can be used, to help dominate SS/D. NHRA gets wind of this, and says 'no way'. The 70' car is actually longer than the 69' car, and is not the same car The 70' heads cannot be utilized on the 69' car for Super/Stock, but Modified Production would be fine. AMC was not about to spend another $250,000 building 50+ 70' AMX Super/Stockers. PC |
Re: 69' amx
You have it right except I really don't think the -291 head for 1970 was a part of the equation. If it were, AMC would have sent a pair of heads out with the body parts. I have a LOT of AMC correspondence on the conversion issue and have never seen even a hint about newer heads on the horizon.
I think the only deal was to have a fresh face for the 1970 model year. |
Re: 69' amx
Jeff,
Your probably right. Maybe it was just the 70' nose looked better than the 69'. From an AMC marketing stand-point, the new-style was the way to go. The new 'dog-leg' heads would only work, if they went through 'Crane' for modifications. Maybe AMC's original thought was to try to back door the newer heads on to the 69' S/S cars, after they were converted to 70' cars. Greg Long of AMC (Elmsford HQ), said, he thought that AMC would be willing to build (7) 70' AMX S/S cars (in January 70') with the new style heads. Once out there, they would push the 70' conversion kits for the 69' S/S racers. PC |
Re: 69' amx
AMC sent the upgraded 70 kit to the SS/AMX owners purely as a marketing idea. The 70 AMX had a big facelift-nose, taillights, interior, and wanted to promote the new 70 model line. The heads were also much better, and larger head bolts as well, but this was never part of the upgrade. Didn't other manufacturers change grills/taillights as well to upgrade to a newer model year?
The improvement of the heads was not done by Kaplan, but rather in-house by the engineers that ran the flow bench and other testing equipment. They tried to sell the idea to AMC when the 390 came out-and improvement that actually cost no extra money, just a redesign casting. One of the engineers actually raced an original SS/AMX at the Nationals-the purple one shown in the staging lanes. he later helped write Performance American Style, a early "bible" for AMC enthusiasts sold at the dealers parts counters. AMC and Hurst redid the original set of heads used on the prototype Super Stock car, but did not have the time/facilities to do a run for all the cars, so sent them to Crane. Spoke to the original owner of an SS/AMX yesterday. He also swapped the parts to an upgrade 70, but as he only raced at a local track he did not have to change them back. |
Re: 69' amx
Good point to Paul about the head bolts. The 1970+ blocks / heads were a 1/2" head bolt while the 1969- blocks / heads were a 7/16" head bolt. Putting the 1970 heads on the 1969 short block would have required reducer bushings in the heads or drill / tap to the block.
|
Re: 69' amx
Tom is right the 69ss/amx was for many years was the most factored. factory rating 340hp NHRA factor 420hp a 80hp increase the hemi's went from 425 to 500hp a 75hp increase. The 69 factory ss/amx now has 407hp rating.
|
Re: 69' amx
Jeff,
Article in 1970 Car Craft, mentions that the over-all length of the 70' AMX (longer than the 69') with the newer nose, was the big issue with the NHRA, not the new head conversion (if performed). They were convinced (it doesn't mention names) that it would be protested, because of aerodynamics. As you know, the 70' AMX car was 1" lower (newer front-end suspension changes) and 2" longer (extended front-grille and hood) than the 69' AMX car. Ozzie, In 68' the AMX was available with other engines, not only the 390/315HP engine. The 343/280 HP and the 290/225HP were both available in the first year run AMX. In 68', the AMX; NHRA class; (390/315HP; #3163 lbs.= E/Stock), (343/280HP; #3096 lbs. = G/Stock). For some reason, a lighter weight was factored for the 290/225HP AMX (#2836 lbs. = J/Stock) Not the currently listed #3096 lbs. Also, the 68' Javelin SST 290/225HP was also classed in J/Stock. I think the listed weight has since changed. In 69', the 68'AMX 390/315HP ran in F/Stock, or SS/J (see; Ross Gilbert) Paul |
Re: 69' amx
Ozzie,
I'm not sure, but I think the 69' AMX was lighter than the 68' AMX. Not sure why? I thought they were the same and one? I'll check, but if your correct, than in 69', the 69' AMX 390/315HP ran in E/Stock and the 68' AMX 390/315HP ran in F/Stock. PC The guidelines list the 69' AMX 390/315HP at #3048 lbs. (-115 lbs.) lighter than the 68' AMX 390/315HP, so it would be classed one class lower. Though the 69' AMX 343/280HP and 290/225HP cars are listed with almost the exact weight. I'm lost! The S/S car is also listed at #3048 lbs. There has to be some error.. As for other classificatiions, I know for a fact that we ran against a 68' or 69' Javelin SST in 1969, in K/S (12.50-12.99 wt/hp) Ran against him the whole summer. The current weight/hp factors don't compute, but I'll figure it out. |
Re: 69' amx
Ozzie,
It must be an error in the AMX weight listing. The 68' and 69' 390/315HP weighed in almost exactly. In 68', the car would be classed in E/Stock, and in 69' the car would be classed in F/Stock, and/or SS/J. As for the 290/225HP engine. One listing has the Javelin SST with a weight of #2836, which equates to K/S (12.50-12.99 wt/hp) in 1969, like I said. There are some refrences, that show the 290 (N-code) engine with a 235HP rating, in the AMX, but 225HP in the Javelin. Not sure if there were any differences, maybe in the exhaust system? In any event, the old listing shows the 68' AMX 290 engine with a weight of #3046 lbs. If they factored it by 235HP, it would also be classed in K/S in 1969. PC |
All times are GMT -4. The time now is 08:43 PM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
Copyright Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.