Can I put a 425 nailhead, switch pitch tranny, and posi rear from a 66 riviera into a 66 lesabre? Would any of this combo work for my application? Anyone know what challenges i would be up against? Or what type of performance i would get? My aim is to get a little more ummph out of the flagship cruiser. Meanwhile is there any other tranny that could mate to the 340? And what needs to be adapted? Thanks Jamiel
Wildcat? Jamiel, :3gears: The easiest thing to do for increasing the performance of a 66 LeSabre is to do what buyers did in 66, move up to the Wildcat, the 425, SP 400 could already be there, maybe the posi as well. If that is not in the cards . . . The swap you talk about is possible, but not all of the components will fit without some modification. The Riv rear axle is from an X frame car, yours is a perimeter frame car, mount points are different. The 425 and SP 400 trans will swap in, but there could be issues with exhaust and steering linkage that could get expensive. I have heard differing views on the reason for the length difference between the LeSabre and Wildcat, some guys say the length is in the quarter panels, some say it is in the front fenders. If the front fenders are shorter on a LeSabre, it could make the engine compartment smaller and then less clearance for the nailhead. The GM 2004R will bolt up to the back of your 340 and give you some performance and fuel economy gains. This modification is something a do it yourself type guy can pull off, depending upon your level of skill or the thickness of your wallet. Give some more detail and we can give you more advise and pointers, just don't small block chevy it! Tim :beer
No SBC here... 200r4/700r4 I wouldn't go in the SBC direction. Sadly the tranny alone is an upgrade necessary to get better gas mileage, its a rebuilt original that shifts extremely smooth. My goals are to get some more power out of the car and the 2speed just seemed to "coast" to 40mph LOL I know its carrying alot of weight, but i aim to get a little quicker acceleration. Im on a budget, and since the 425 combo swap could be costly, I'll attemp to drop in in a transmission. In newbie terms, what do I gain? Can anyone tell me the difference between the 700R4 and the 200R4 and where to find either? I thought I read somewhere that the 700 was tougher? and they can be found in 87-96 Gm cars +trucks? Thanks Jamiel
2004R Versus 700R4 Jamiel, The usual choice for upgrades depends on your vehicle. The 700 has had 15 years more development than the 2004R, which was discontinued in 1991. However, the 200 bolts up to your engine without a transmission adapter, which saves a large amount of money on your swap. If you are on a budget, that would be the way I would go. The modern four speed automatic gives you strong acceleration because of the low first gear ratio, but also gives you good fuel economy because of 4th gear being an overdrive, where the engine turns slower than the driveshaft. A 340 in a full size like the LeSabre is not going to be a stout performer without significant modifications. The 401-425 would help, but most likely the easiest way to boost power would be a 430-455, which should fit your car with less hassle factor than a nailhead. Again, all of these swaps require some experience or a large bank account or both. The worst thing that could happen is for you to attempt to modify a running car and run out of time or ambition before completion, no one wants to see that! Good luck with whatever option you choose! Tim :Comp:
