3.5 - 4.0

I got the history on why you want to do this, from the previous thread, but, as Disco says, what would posses you to put a 3.5 in to replace the bad 4.0?
A 3.9 would make more sense, as you wouldn't notice a power difference. but the 3.5 is going to feel like your 4.0 on 6 cylinders.

The bottome line is, if you were willing to go to the bother ( alot of labor is going to be invested here, not to mention the cost of parts to convert the 3.5 to a GEMS block) is that you would need to strip the front cover (oil pump and distributor) off, and replace it with the front cover and oil pump from the 4.0. Also the intake manifold from the 4.0 must be put onto the 3.5 as the fuel rail and throttle body( including the 4.0 MAF) must be retained to satisfy the GEMS ECU.

Thinking about it, I suppose you could leave the 3.5 front cover, including the distributor, in place, just changed over the top end. Man would that blow some mechanics mind when he opened the hood and saw no wires coming off the distributor to the plugs.

Personally, if it were me,and knowing what a pain in the ass it is to pull these hunks of aluminum out, I would only go through it once. If the money was an issue, I'd go find my own 'Desperate Housewife' and be her bitch.

onslow said:

Sorry chaps but I totally disagree (as usual) :dunno:

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Sorry, Ons, but in this case I have to disagree with you. The reason Spool indicated choosing a used 3.5 was cost savings. That being said, how much is any cheap engine after you tear it down to change the cam, cam bearings replace the lifters (You wouldn't put an ancient set of lifters atop a new cam would you?)
He would then have to either polish the ports himself, or send the heads out to have them done, polished and port matched. I don't know what your shop charges, but most automotive machine shops around here don't come cheap.(yeah, I know, you do it yourself right, so do I but Spool hasn't indicated he would) So, basically, he is completely rebuilding a 3.5, and it would have been more prudent to have taken all those steps, but on his original 4.0 (and not have wasted the $$$ on the 3.5 to begin with)
After all thats done, he still can't put the 4 barrel on(4barrel and manifold, another $800), as most states won't permit it, and it won't pass emmissions, and most states are now testing that too. He's working with a GEMS ecu system, and there will be problems in the ecu isn't seeing a running engine, and GEMS is also security critical, imobilizer and all Any 3.5 is going to 8 years old now, and probably a high miler. True that 3.5 engines never ( I never heard of one) had liner shifts, though they are know just as 3.9 and 4.2 for needing head gaskets as they age, steel head gaskets simply don't last forever.
So his "reasonable" 3.5 is now, conservatively, pushing $2500.

I just recently did a total on a 4.2 and with shop work and parts, was over $2k, and I don't put any price on my labor.
He hasn't indicated, but if it's a standard (R380) it isn't as critical, but if it's a ZF4, the gearbox govenor is likely to delay his shift. I agree, a removal can be done in a day, but he's not going to 'pop' the new one in the next day, as there are loads of bit and pieces to swap over, unless he's prebuilt the new 3.5, and gotten the flywheel with it (or torque converter plate)
I wouldn't disagree, a 3.5 with a Holley is basically what every healey owner wanted 25 years ago (There were lots of these around from Buicks) an I have one sitting out on the shop floor right now with a top mounted turbo and side draft carburator, and it will probably still sitting there when I'm dead and gone.
A 3.5 in your S1 must make it go like snot, but the S3 Stage one was a piece of Heath Robinson if I ever saw one, whoever designed that trans should have been shot.
I stick by my original statement; puting a 3.5 in his Disco would be a mistake.
(Besides, he seems to have gottewn religeon, and says he will seek out a 4.6, Now that's going in the RIGHT direction.