Recommended Performance Motor Swap

[DarthRevan39]

Hey all,

This might be heretical to suggest, but my shop mentioned that my 429 in the 71 seemed to be a little weak and I've been giving some thought in replacing it with a new performance motor of some kind. Probably would replace just about everything at once, motor, drive train, suspension etc. Looking mostly at the motor in this thread, do you guys have any suggestions for high HP/torque motors that will fit? Probably looking in the $5k-$10k range.

Thanks in advance and looking forward to your suggestions!

 

[mikeyhunts]

460 stroker would be awesome!!!

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[rvrtrash]

A picture is worth a thousand words. More than $10K, but.......

https://jonkaaseracingengines.com/shop/boss-nine-parts/custom-bulit-boss-nine/

Steve

 

[donkost]

Is it a original 429 car with a numbers-matching or at least date-correct block? if so, it's of course up to you but you should probably rebuild that one and keep it in the car from a historical perspective. Do you agree with your shop that it's weak? What are compression and other readings? Depending on the state of the block and any past rebuilds, maybe you just need a hotter cam and some other standard performance mods along with some really focused tuning. If you're not concerned about numbers-matching and the 429 is truly shot, then sure a built 460 seems like a good avenue to take. Your suspension and other items are already likely set up to handle the big block.

 

[mustang7173]

I agree with donkost, I can see a fresh up rebuild with hydraulic roller cam system, and roller rockers. I do know that the 1970 Cyclone 429's had 375 hp. from the factory. Maybe you can look at the compression and other specs to mimic that 429.

 

[jowens1126]

Theres alot you can do with a "385" series 429 now. You can get some John Kaase Racing goodness for it that will launch you to the moon. All it takes it Money, lots of money.

https://jonkaaseracingengines.com/

https://jonkaaseracingengines.com/shop/engines/kaase-p-51-engines/#

 

[Hemikiller]

my shop mentioned that my 429 in the 71 seemed to be a little weak

... and what evidence did they provide to support that claim? "Weak" is a rather subjective opinion. If they did a leakdown or compression test and the numbers came back bad, or you're using an excessive amount of oil, then okay. However, to start considering dropping $10K on the suggestion from a shop (that I'm sure would love to get paid to do the work) "thinking" your engine is weak?

IMO, do a compression and leakdown test. If the numbers how you have a problem, then go from there.

 

[Stanglover]

Hey all,

This might be heretical to suggest, but my shop mentioned that my 429 in the 71 seemed to be a little weak and I've been giving some thought in replacing it with a new performance motor of some kind. Probably would replace just about everything at once, motor, drive train, suspension etc. Looking mostly at the motor in this thread, do you guys have any suggestions for high HP/torque motors that will fit? Probably looking in the $5k-$10k range.

Thanks in advance and looking forward to your suggestions!

 Only heretical if you're considering a "Chevy" motor!!

Just wondering if your "shop" guy is wanting to screw you out of the 429. Weak or not, make sure you don't get "talked into letting it go for "scrap" if you get my meaning.

If the block is still good, rebuild it would be what I'd do.

Geoff.

 

[DarthRevan39]

my shop mentioned that my 429 in the 71 seemed to be a little weak

... and what evidence did they provide to support that claim? "Weak" is a rather subjective opinion. If they did a leakdown or compression test and the numbers came back bad, or you're using an excessive amount of oil, then okay. However, to start considering dropping $10K on the suggestion from a shop (that I'm sure would love to get paid to do the work) "thinking" your engine is weak?

IMO, do a compression and leakdown test. If the numbers how you have a problem, then go from there.

I would agree with them that it doesn't seem to be strong especially during idle. I do need to do a leakdown test for sure. Probably should check the spark plugs and distributor first too. I think "tired" was the actual terminology they used.

I don't think this shop offers engine swaps so they aren't really trying to screw me. This is also something I'm just thinking of doing in the future. It isn't the original block either because the original was a 351 according to the VIN. It's one of those instances where I got the vehicle from a person who did a partial restore and they didn't exactly do the best job and I'm not even sure what all they did or where this block came from. The engine probably needs a whole teardown, inspection, and cleaning TBH. I do like the idea of doing a 460 Stroker if I'm going to go through the trouble of a teardown.

Really just looking for different opinions and to see what people have done to get ideas for the future.

 

[DarthRevan39]

A picture is worth a thousand words. More than $10K, but.......

https://jonkaaseracingengines.com/shop/boss-nine-parts/custom-bulit-boss-nine/

Steve

Man that would be awesome to put in! Worth more than the car itself though. Honestly might consider it in a few years lol

 

[DarthRevan39]

460 stroker would be awesome!!!

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I really like the idea of doing that if the block is still solid! Thanks!

 

[DarthRevan39]

Is it a original 429 car with a numbers-matching or at least date-correct block?  if so, it's of course up to you but you should probably rebuild that one and keep it in the car from a historical perspective.  Do you agree with your shop that it's weak?  What are compression and other readings?  Depending on the state of the block and any past rebuilds, maybe you just need a hotter cam and some other standard performance mods along with some really focused tuning.  If you're not concerned about numbers-matching and the 429 is truly shot, then sure a built 460 seems like a good avenue to take.  Your suspension and other items are already likely set up to handle the big block.

It's not the original motor with the car as it came off the line with a 351. I spent a good amount of time trying to find the serial number yesterday so I could look it up, but I'm not sure where it is located. I agree it is weak at idle at the very least. There's a number of things that I should check first, but I kinda want to do a rebuild or swap anyways so I can make sure it's done right.

 

[c9zx]

Figure out what your budget is and contact these people http://reincarnation-automotive.com/home  Chuck

 

[donkost]

Well I'd take a engine that is weak at idle, as long as it was strong while accelerating. Sounds like you are geared up to spend money on it, but step back and evaluate the critical values of the present engine. If it's a 429 that's still something good to work from, a torque monster. Remember also if you put $10K toward swapping out the drivetrain you'll never get that money back as far as the value of the car. I'm sure you are aware of this, and cars are sold and auctioned off each day for half of the money that was put into them during a restoration. If the car is solid otherwise, no rust and so forth, then you likely plan on holding on to it for a decade or so and using it as a platform for increasing performance, without regard for selling price.

 

[jpaz]

Week at idle? What is that supposed to mean? Just because it’s not idling or running correctly? It may just need a proper tune up or it may just need to have the carb rebuilt. But I do know what you mean by not really knowing what was done to the engine. I was told that certain things were done to my engine when I bought my car, but I was basically lied to. My engine was built very poorly and I’m lucky I didn’t have a catastrophic engine failure. Same thing for my transmission too.

It may be cheaper in the long run to just get it rebuilt, providing that the block checks out good. Hopefully you can get it checked out and be able to drive it. Good luck!

 

[DarthRevan39]

Thanks for the suggestions everyone!

Yeah I just turned 25 and this has been my dream car since I was 15, got pretty lucky in that regard to being able to own my dream car so young. Don't get me wrong the vehicle is perfectly drivable and I am enjoying it! I just want to make it just about as good as it gets and I have no intention of selling it in the future as long as my life permits me to keep it!

Also with few other expenses in my life, I'm fairly comfortable with spending money on it because I am still able to put away plenty of money for myself with my job. I am also value oriented to an extent, so if I think I can do a rebuild of the engine or proper repair/tune up for cheaper and get more value out of it then a new motor then I will, but if I think I'll get more value out of dropping money into the black hole I will do that too! Lol

 

[mikeyhunts]

Thanks for the suggestions everyone!

Yeah I just turned 25 and this has been my dream car since I was 15, got pretty lucky in that regard to being able to own my dream car so young. Don't get me wrong the vehicle is perfectly drivable and I am enjoying it! I just want to make it just about as good as it gets and I have no intention of selling it in the future as long as my life permits me to keep it!

Also with few other expenses in my life, I'm fairly comfortable with spending money on it because I am still able to put away plenty of money for myself with my job. I am also value oriented to an extent, so if I think I can do a rebuild of the engine or proper repair/tune up for cheaper and get more value out of it then a new motor then I will, but if I think I'll get more value out of dropping money into the black hole I will do that too! Lol

If you got it, drop it!

Burn outs are fun!








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[Jeff73Mach1]

Starting point is an honest assessment of the current engine. To do so, you can do a compression and leak down test. A vacuum gauge, however will give you a quicker idea of what is going on.

I would also recommend plugs wires cap rotor and timing all be set as well, check for vacuum leaks and add a fresh fuel filter and if necessary an overhaul of the carburetor. A weak motor is often a poorly tuned one. Until it has a proper tuning, thinking about pulling and replacing it is just silly. If you can't tune a motor. . . you can't really install one properly.

 

[EdM]

I went with a crate engine from a local builder, Smeding Performance, and their milder Dart based 427 Windsor. My car was a Q-code 351 Cleveland. I could not be happier. A great street engine.

https://smedingperformance.com/collections/ford/products/427-windsor