Guest 400 ci 280z Posted July 8, 2002 Share Posted July 8, 2002 grog, i am putting a pont 400 in my z and was wondering how you did your motor mounts? i am still at my dads and have not been able to mess with the car. could you help me with this? Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 10, 2002 Share Posted July 10, 2002 could someone help me with this? Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted July 10, 2002 Share Posted July 10, 2002 It's not a common swap so that is why no one has come up with anything yet. I am a pontiac fan from a long time back but I choose a small block ford to put in. Even with a ford I still have the same problem you do, how to mount the engine. I am doing a lot of welding on the bottom so whats a little more for engine mounts. That thing is going to have a real problem with traction, a real problem with a lack of it. Good luck Don Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 10, 2002 Share Posted July 10, 2002 i know it will have a traction problem but i will try to solve that later. also i have not been able to work on my car in a few months because i am visiting my dad in iowa. so i have not been able to try and work on motor mounts. i have tried to get one member that has done this with a 455 to help me out but he never got back to me. i also noticed that grog put a 350 in his so i was going to ask him how he did his. Quote Link to comment Share on other sites More sharing options...
Grog Posted July 10, 2002 Share Posted July 10, 2002 Chris, First, what year is the engine block? Second, regardless of year, you will need the original motor mounts that attach TO the block. Third, plan to do some welding. From there, I can give you the specfications on modifying the mounts to attach to the stock crossmember. Depending on your preference, you can use mounting isolators or go with a solid spacer in between the mount and crossmember. I have had my Poncho in my Z for 2 years now with no problems. The motor mount modification is VERY simple. On a related note, I strongly recommend not using the T400 transmission unless you plan to gut the transmission tunnel. The B.O.P. T350 works equally well (I use it) and requires no additional modifications. You just need to use the appropriate flexplate and the transmission will bolt right up. Also, the 200R4 tranny will bolt up as well. Some folks might say it's weak, but it is tough enough to handle the abuse from the Buick GN's and Regal T-Types. I have info for this swap as well. If you need any advice on performing the Pontiac swap, let me know. Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted July 11, 2002 Share Posted July 11, 2002 I would use a M-20 not a M-22, the M-20 were a wide ratio box and is better suited for the pontaic torque. I had a M-20 in one 65 goat and a M-21 in another and just hated the M-21. The M-22 has the same gear set as the M-21 (If I remember right, 20 years is a long time). I would try to get a R200 with a 3.3 gear set (I think Ross C has a gear set) And use the M-20 but that just me. Don Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 11, 2002 Share Posted July 11, 2002 i have a 69 block but do not have the mounts for it because i got it from an uncle. he just had the engine sitting in his garage and gave it to me. i will most likly use a manual trans(m-22) instead of an auto. if you wouldnt mind telling me what i need to do to the mount would help out a lot. did you move the engine back or lower it any? grog thats a lot for the help ! Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 11, 2002 Share Posted July 11, 2002 thanks for the advice about trannys and i will look into that. thanks Quote Link to comment Share on other sites More sharing options...
Grog Posted July 11, 2002 Share Posted July 11, 2002 Chris, You will have to obtain motor mounts for the 69 block. These can be acquired from Year One (http://www.yearone.com), a Pontiac restoration store that offers new mounts for ~35 USD. Friendly and knowledgable folks staff the customer service desk. I will take a few digital pictures of my mounts since they will be identical to the ones you will need to fabricate, along with a diagram of what you will need to modify to make the mounts work and other pictures that will be beneficial to putting a tiger under the hood. Word of caution -- the Pontiac block is VERY wide. This is noticably evident once you put the engine in and get a good look at how the exhaust will interfer with the steering shaft. If you can't afford to fabricate a very expensive set of custom headers to overcome the problem, then you must modify the steering shaft to accomodate the stock exhaust manifolds. I did this with minor effort and use stock center dump cast iron manifolds available from your local junkyard. Ram air manifolds will not work. Also bear in mind the Pontiac designed their engines using the same tooling to produce the 350-455 engines. the only major difference between these engines is bore and stroke. Therefore, once you make the mods to accomodate a P-400, they apply to the 350, 428, and 455 engines. Talk about versatility! Give me a day or so to get the pictures and diagram together and I will email them to you. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 11, 2002 Share Posted July 11, 2002 Isn't the M22 the famous 'Rock Crusher' ? Close ratio gears I agree wouldn't be the plan for a motor with that sort of torque. I like the poncho motors quite a bit, a partner had a 350 HO firebird (68 I want to say) with a 4 sp and 3.90 posi and for a car running red wall tires of who knows what sort of traction ability, but that car would literally leap when he banged second, no drama, just a set you back in your seat second gear. Very impressive for a stock motor. The block size is cool too, wide as mentioned but the only other motor I can think of that spanned those sort of displacements on the same block was the AMC V8 (304 inch to 401 inch all the same block). Wasn't the head swapping pretty good on Pontiacs too? (meaning you pull a head from another year and bam your compression is raised by alot?) Anyway, should make a nice cruiser, there 400 was awesome and even though it was smogged down, my friends mom's 455 GTO (last year the one that looked like a nova hatchback basically) still had amazing tire lighting abilities. Good luck with it and send some picts when thats in there, I'm sure more of us would like to see it. Regards, Lone Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 11, 2002 Share Posted July 11, 2002 grog that is one thing i like about the pont motors. if you have a 350 a decide you want something with more cubes the only thing you need to do is pull the motor and drop in a bigger one. again thanks a lot for the help. lone your right about the heads. what you can do is take the heads off of your low compression engine and slap on a set of the old heads (which i think are 72cc) and you are set to go. Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted July 12, 2002 Share Posted July 12, 2002 Grog, please post your diagrams, etc. here. I am always interested in the more unusual swaps, and I would love to see how you stuffed that engine in a Z. Quote Link to comment Share on other sites More sharing options...
Grog Posted July 14, 2002 Share Posted July 14, 2002 Before you consider performing a head swap on a Poncho -- do your homework. Not all the heads are interchangeable depending on year and engine displacement. Also, swapping out large chambered head in favor of some of the smaller chamber heads could result in TOO muchcompression and make the motor undrivable (or cause serious damage). Generally, Ram Air heads and some earlier castings from the 350 and 400 engines have small chambers at approx. 72cc's. Swapping these on a later model or non-Ram Air engine could cause problems so, as a minimum, you must do the math and calculate your final compression ratio and measure valve to piston clearance. The best thing is to find a cheap set of 6X heads off the 350. They have 91cc chambers as opposed to the 6X heads off the 400 which are 98cc. The 6X heads are the best of the D-ports, and with mild port work flow better than any of the Ram Air heads. Plus, you wouldn't have to use Ram-Air exhaust manifolds-- which as I mentioned before will not work in a Z. You could use the Edelbrock heads but the only real benefit is a weight savings. Remember, on a Pontiac engine that every 0.006 inches milled off the heads is equivalent to shaving off 1cc. For mminimal expense, take a set of 6X heads to your local performance shop and have them mill 0.012" off the deck and that will give you the chamber volume you need and still keep the motor streetable. I am still getting the pics together, and at Lone's request, will post them on the site. Cheers, Grog Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 14, 2002 Share Posted July 14, 2002 grog is right you do not want to just take any set of heads and put them on but if you had a 455 and wanted better cr than you could take the heads off the 400(98 or 101cc) and get the higher cr. i have the 6X-4 that are 91cc and i am just going to mill them down so i will get 9.5 cr or just a little under. Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 16, 2002 Share Posted July 16, 2002 grog, i was just wondering if you were able to get that stuff together. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 19, 2002 Share Posted July 19, 2002 Motor mounts should be the same as a standard SBC, I beleive.. I have a 71 Lemans with a pont 400 also, the heads and header layouts are different then chevy, the intake manifold is slightly different but as far as the block's cast internals are identical to the chev 400 (im assuming), if you have the block out on a stand try mounting up the chevy mounts and see what you get.. im not 100% sure but this is my guess. Dan Quote Link to comment Share on other sites More sharing options...
Grog Posted July 19, 2002 Share Posted July 19, 2002 Chris, I have gotten a large volume of requests for info on the Ponch swap. This has prompted me to my knowledge and pics of the swap on a webpage. I am in the process of posting this information on the website. I will let you know immediately when itis up, which should be within the week. It will be crude since this is my first attempt at web publishing, so please be forgiving. Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted July 19, 2002 Share Posted July 19, 2002 Yes the pontiac rubber mounts are diffrent but if you unbolt the steel mount that mounts on the frame you can bolt on chev mounts. This just hit me when I was reading this post, are the JTR mounts for a chev just a plate that you mount the steel mount for the rubber to mount on? If it is, couldn't you just swap out the steel chev lower mount to a pontiac and just use the rubber pontiac engine mounts. If anyone could follow that, would it work? The distances to the firewall should be the same because you can swap pontiacs and chevs. Just a thought. Don Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 20, 2002 Share Posted July 20, 2002 i am almost positive that the chevys and pontiacs do not have the same bolt locations, but i could be wrong. Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted July 20, 2002 Share Posted July 20, 2002 The frame holes that mount the lower part of the motor mount are the same in place in GTO, chevelle, 442/cutless, skylark F85.... Those cars used the same frame as did the camaro/firebird. Thats why chev swaps were so easy into other GM cars. I took a BBC out of my GTO when I bought it just so I could put in a (the?) proper engine. No flames please, I mean I am putting a ford in my Z. Don Quote Link to comment Share on other sites More sharing options...
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