PLEASE help me decide!!

[gtotto]

Hey guys,

I'm in the process of restoring/modifying my 65 GTO and REALLY don't know what to do about my power plant. I have a pontiac 421 that I planned on rebuilding, adding EFI, a serpentine setup, etc. etc. and then mate it up with a TKO 600. Now before I take that financial plunge, I want to consider LSX options. I know the LS motors are the latest and the greatest, produce alot of power and will be around for a long time. My main concerns, obviously, are the cost and pains in installation. I would like to be in the 500-600 HP range and would be driving the car everywhere. (I know, I know the LSX gas mileage can be awesome)

The 421 came out of the car and will go back in just as easliy. Spark, fuel, and the throttle cable and I'm back in business. Not a whole lot of fabricating/cutting with a TKO tranny but there is some. I do think it's kinda cool to have an old school motor with modern upgrades but it still is old technology.

The LSX platform offers new technology, lightweight block, tons of options, power,etc. I have been on this site for a while and see alot of you guys running LS' and loving them . My concern is that there seems to be a TON of considerations when retro fitting these drivetrains into an old A-body...am I wrong? am I over analyzing?? My fear of the LS falls in the "nickel and dime you to death" area with all the different oil pans, relocation brackets, accessory drives, etc.

Opinions please!!!

[Lowend]

If it's a "real" GTO, than I would not swap an LSx motor. You already have a solid running pontiac engine, do an EFI swap and keep it all Poncho
Paul Caselas is over at http://mustang-corral.com/ now. He's done some Pontiac EFI conversions using original manifolds and they are pretty damn cool

[78 Type-LT]

LS motors are sweet, but sence you have a gem like a 421, that with EFI. would be cool.

[ProdigyCustoms]

When we did Bill s GTO we got some grief from the Pontiac crowd for putting a LS motor in it. When we did EmptyNest I remembered that and I stuck with a "real" Pontiac motor in EmptyNest out of respect to the Pontiac crowd. it did not matter, they showed no respect to the vehicle.

I would do a LS if I do it again. For what I spent on that Pontaic I could have had the worlds baddest LS motor!

JMO

[Jim Nilsen]

When we did Bill s GTO we got some grief from the Pontiac crowd for putting a LS motor in it. When we did EmptyNest I remembered that and I stuck with a "real" Pontiac motor in EmptyNest out of respect to the Pontiac crowd. it did not matter, they showed no respect to the vehicle.

I would do a LS if I do it again. For what I spent on that Pontaic I could have had the worlds baddest LS motor!

JMO

I would think that an LS motor that was the worlds baddest would get respect from someone.LOL

Get a little respect and go LSX

[Mkelcy]

Hey guys,

I'm in the process of restoring/modifying my 65 GTO and REALLY don't know what to do about my power plant. I have a pontiac 421 that I planned on rebuilding, adding EFI, a serpentine setup, etc. etc. and then mate it up with a TKO 600. Now before I take that financial plunge, I want to consider LSX options. I know the LS motors are the latest and the greatest, produce alot of power and will be around for a long time. My main concerns, obviously, are the cost and pains in installation. I would like to be in the 500-600 HP range and would be driving the car everywhere. (I know, I know the LSX gas mileage can be awesome)

The 421 came out of the car and will go back in just as easliy. Spark, fuel, and the throttle cable and I'm back in business. Not a whole lot of fabricating/cutting with a TKO tranny but there is some. I do think it's kinda cool to have an old school motor with modern upgrades but it still is old technology.

The LSX platform offers new technology, lightweight block, tons of options, power,etc. I have been on this site for a while and see alot of you guys running LS' and loving them . My concern is that there seems to be a TON of considerations when retro fitting these drivetrains into an old A-body...am I wrong? am I over analyzing?? My fear of the LS falls in the "nickel and dime you to death" area with all the different oil pans, relocation brackets, accessory drives, etc.

Opinions please!!!

Once you've decided that your choice is LSx or EFI 421, a lot of the "nickel and dime" stuff is off the table. You'll need to redo the fuel system either way and you'll need to install the EFI wiring harness, ECU, etc. in either event. Physically putting an LSx engine in the car is pretty easy, and there's a lot of advice out there already on what works and what doesn't

The major difference is that the LSx is easily and relatively cheaply available, and there are lots of tuners out there who can get them running well, regardless what mods you make.

An EFI 421 is not going to be quite as easy. You'll need to select an engine management system that either you can tune, or is supported by a GOOD local tuner. You'll also have the cost of building the engine itself and modifying the intake.

I'm not sure what your budget is, but you can get new 480 hp LS3's (which are capable of MUCH more power) with a new factory programmed ECU, new wiring harness and factory style accessories for about $8,000. You can also score LSx engines from a variety of sources, etc. for much less.

I debated this for a long time myself with my '68 and '67 Camaro projects. Even though I had a really nice, fully built AFR headed, forged bottom end 465 hp 383 SBC sitting in the shop, I finally decided just to go LSx and be done with it for all the reasons you cited - mileage, easy power, virtually leak free, lots of support, etc.

Finally, nothing involved in the LSx swap is permanent. If thr 421 is original to the car, preserve it and stick it in the back of the garage for the future buyer who just has to have a period correct engine in the car.

[alnoe]

Build the car to make yourself happy. If a "purist" does not like it, don't sweat it. You did not build the car for them!

[Lowend]

I've shown this pic more than a couple times - but BAM
https://static1.pt-content.com/images/pt/2005/06/tripowerincar-1.jpg

[gtotto]

I did forget to mention that the car is only a clone and the 421 is not original to the car so I really would not be devaluing it by changing things. Also the car is for me and my wants/needs not someone else. I appreciate all the input guys, I just need to go in a direction!!

[b-man]

If you want things to be easy, keep the Pontiac engine.

The LSX swap isn't exactly plug and play.

I'm putting an LS3 into a '64 Tempest, there are lot of little things involved in making everything fit that you wouldn't have to deal with if you kept the Pontiac engine.

It's all in what your final goal is. I wanted to knock some extra weight off the front of my car, so the LSX was the only economical way to acheive that. I also wanted the best gas mileage possible, you get that with the LSX engines especially if you decide to keep the stock cam.

[wmhjr]

It's really about you answering your on question. Nobody else can make that decision for you.

Your car is not a "Factory GTO" so you should feel perfectly OK making whatever changes you like with no reservations.

To me, the traditional Pontiac standard block just preserves the feel of the "muscle car". In my project I knew that while the car will get driven, I don't plan tons of miles. So, any little inconveniences coming from a traditional standard block making close to 600hp were actually desirable to me. I WANTED a little rough idle as a result of the aggressive cam.

If I planned to do more long distance driving I might well have opted for an LS combination. Smoother, better mileage and maybe higher reliability.

Figure out what you want out of the car and build it that way. Either way is a winner.

A caution on one thing. The Pontiac A-Body is not exactly the same as the chevy. Different steering, etc. Enough differences that you should expect a little variation from what the guys in the chevelle crowd experience if you make major changes. Things like differences in Idler arms, tie rods, center links, etc.

[gtotto]

If you want things to be easy, keep the Pontiac engine.

The LSX swap isn't exactly plug and play.

I'm putting an LS3 into a '64 Tempest, there are lot of little things involved in making everything fit that you wouldn't have to deal with if you kept the Pontiac engine.

It's all in what your final goal is. I wanted to knock some extra weight off the front of my car, so the LSX was the only economical way to acheive that. I also wanted the best gas mileage possible, you get that with the LSX engines especially if you decide to keep the stock cam.


Thanks for your input. I have watched your build (which is awesome!!) and have used your thread as a "decisional aide". I plan on using a manual tranny so I might not run into some of the headaches you have had with the auto trans. My mixed thoughts about the 421/LSx dilemma is the 421, up front, is easier but the LS, and it's current and furture aftermarket advantages, will be around for a long time. The more I think the more I go insane!!!

[gtotto]

It's really about you answering your on question. Nobody else can make that decision for you.

Your car is not a "Factory GTO" so you should feel perfectly OK making whatever changes you like with no reservations.

To me, the traditional Pontiac standard block just preserves the feel of the "muscle car". In my project I knew that while the car will get driven, I don't plan tons of miles. So, any little inconveniences coming from a traditional standard block making close to 600hp were actually desirable to me. I WANTED a little rough idle as a result of the aggressive cam.

If I planned to do more long distance driving I might well have opted for an LS combination. Smoother, better mileage and maybe higher reliability.

Figure out what you want out of the car and build it that way. Either way is a winner.

A caution on one thing. The Pontiac A-Body is not exactly the same as the chevy. Different steering, etc. Enough differences that you should expect a little variation from what the guys in the chevelle crowd experience if you make major changes. Things like differences in Idler arms, tie rods, center links, etc.



Thanks for responding. I've been watching your progress with that gorgeous car of yours....keep up the good work!!

I agree with the "muscle car feel" and do believe there is a certain cool factor in an old poncho block. There also is a cool factor in a modern plant in a 45 year old car. I do plan on driving the car a bit and would like to do the Power Tour etc etc. Gas mileage aside, I would not mind a long trip with a little bump in the idle, so long as I could depend on making it from point A to B without problems. Decisions, Decisions