ATK vs Blueprint small block crate engines?

[TeeScott]

Gents, I am at a cross-roads with my 73 340 auto challenger. Car has the original drivetrain with 93K miles and runs/drives fine. Engine does not appear to have ever been pulled or worked extensively (original heads, 50-year old internals, etc..). It has some minor blow-by that results in "sporadic" bad odors drifting into the car while driving down the road. It does not noticeably burn-oil/smoke at all, but the sump level does drop slowly (~1 pint) between oil changes. So,....I am currently getting a variety of work done on the car by the Finer Details shop in Indianapolis, and am evaluating options with the staff there to either rebuild the engine OR, swap in a crate 360 magnum-style engine and keep the original engine on a pallet so it can stay with the car for future work/selling with the car someday...
QUESTION: ATK's Crate 360s versus Blueprint's 408 stroker? I hear lots of good reviews on Blueprint engines, but have no direct experience. I also don't have any experience with ATK engines and don't find a lot of reviews/comments. Cost is always a factor, but my goal is to have a reliable, fun cruiser that will lay some decent black marks once in a while and pull similar to the 68-70 340 engines. Comparing long block prices: ATK's 360 magnum with 350 HP 410TQ 360 goes for $4099; while Blueprint's 408 stroker magnum with 375HP, 460TQ flat-tappet magnum goes for $7599; Just not sure that a price difference of nearly twice as high to get into the stroker would really be worth it to me and my use for the car (local cruises and a couple of longer drives to area car events with about 100 mile radius of my home.).
COMMENTS? SUGGESTIONS?
THX-TeeScott

 

[Adam]

A big part of the value of your car is that it’s a original 340 car (even a 73). A 360 engine is a downgrade, in my lowly opinion.

If it were me, I would just rebuild the 340 with some internal upgrades like lighter pistons, roller rockers, etc. If the heads are cracked, keep them in storage, but go with aluminum heads.. same cost, or cheaper than fixing old heads; plus you already have the manifolds, brackets, etc.

I built a 408 stroker. It was a beast, but it got about 10 mpg, and I had to run premium gas. So that may be a a negative consideration.

And a Magnum engine is balanced differently than an LA 360, so either neutral converter and magnum flexplate, or neutral flexplate & magnum converter. Also, are you running a/c? You may have a tough time mounting the original compressor on the magnum. You can run a magnum compressor on an Edelbrock 7577 intake, with the magnum serpentine set up… but you will need custom hoses. I’m sure there are a couple other magnum mods I’m forgetting.

 

[Xcudame]

I agree with Adam, keep it original! A numbers matching 340 car is worth a lot more than one with a 360. Since you have a running driving 340, there not too much wrong with it that a decent rebuild with higher compression pistons wouldn't fix. Plus you can get a stoker kit for the 340 for around $2600, machine work for your block and heads around $2500 (easily) and you'd have a numbers matching beast of a 340/416 small block!

As for you question, cubic inches cost more money the bigger you go. Both ATK and Bluepoint build decent crate engines.

 

[Mopar Nut]

In case you don’t rebuild your 340, contact Johnny Mac at Blueprint engines. he’s a sponsor at FBBO and a vendor at FABO.

 

[Challenger RTA]

Cost is always a factor

I would do a compression and leak down test, then you know the condition. Yeah or Nay. I have done this before with a 4 cylinder in the in truck. Pulled the head and honed the cylinders slapped rings and bearing in. Change timing chain, lapped valves, change valve seals. Cheap refresh, buys time and save money.

It does not noticeably burn-oil/smoke at all, but the sump level does drop slowly

If Main or cranks seal leaking. Sneaky Pete ( That can be done in the car) to change rear main seal. As above do tests. Pull motor and just clean up change rear seal and crank seal. Pull valve covers and put air to cylinders and change valve seals. do timing chain.

The advice above is good. But when you break the engine down. Today you are into BIG money. It's like buying a house you are never done. Just have deep pockets. I just want to say 10K. Not to mention the time it takes to get it done. Not you time, the mechanic and machine shop and getting the parts. To many factors.

That's why I say test. Then see which way to go.

 

[HPP]

IMO, there is no loss in value if the original 340 is retained, even if it isn't installed. If a sale is in the future, then you offer it with the car in addition to the 360, that's a net benefit.

For your use, the 408 doesn't seem to be worth the extra bucks, especailly if you are paying to have all the work done.