I have been a daily reader of this forum for 6 years. I rarely post as im stuck in neutral so to speak and have little real input. I love following the the technical threads.

History and background
I have owned my 1972 340 Demon since my senior year in high school that was 1979.
In the early eighties I played around in the street racing stuff and did a little bracket racing at OCIR.
Then I went back to college got married had kids blah blah. The car was stored in my garage for about 13 years.
I did some basics to get it going again, fuel system hoses, carb rebuilt, Complete brake system overhaul, cooling system, oil, trans oil, plugs, wires, cap
Car fired up ran great and drove it as a toy on weekends for a few more years up to around 2006.
The car has been sitting for the last 8 years. Kids in college and other expenses.

The current setup all mid eighties components except the carb
340 0.030 (original block) #matching
10.5:1 speed pro forged
2.02 J heads port matched pockets cleaned up (original heads with 2.02s added)
Ductile iron adj rocker arms
Comp cams 244@ 50 .510 hyd cam
LD 340 with Carb Shop 3310
B&M LBA rev pattern valve body, not original trans
3400 convertor flashes around 3800
4:10 8-3/4 cone posi
Ran high 12s @ 108 back in the 80s, I always had traction problems with my street tires at OCIR never had slicks, car has stock suspension with no mods

My dream has always been to have a ten second car. This car purely a toy only. I dont plan on ever selling it.
Goal 10.50 somewhat streetable to be able to drive 13 miles to Fontana or 20 miles to Irwindale. Drive around the local area on weekends.

I will be on a tight budget and have to be patient and accumulate parts over time to finish.

The suspension will need to be upgraded no matter what. I will have to go with all the required safety equipment for a 10-11 sec car also

I also feel like i should keep the original engine and go with the two options below.

Option 1) Find a 360 block get fully machined go with 4" rotating assembly ported eddies or used 360-2 heads. Roller or flat tappet. Single plane with bigger carb. Go thru trans have a new convertor built.

Option 2) Find a complete 400 engine/trans cheap. Have block fully machined. Go with a 4.25 stroke assembly, aftermarket alum heads. Indy dual plane. Rebuild trans, new convertor

I know I left a lot of the details out but trying to shorten it.

In the long run what will be cheaper and easier to do ?

Add any thing I left out. No feeling will be hurt on my end.

Final note
My hooker headers are smashed so either option will require headers current trans leaks everywhere from sitting.
Yes I know my 8-3/4 is probably a time bomb.

Thanks Jeff

slap a supercharger on and go racing. forget getting another block, run what you got and upgrade the chassis. then go have some fun.

Leave as is + 150hp nitrous plate kit = dream achieved under budget.

Go 9`s n/a w/a big block AND an 8 3/4..............ftw.

https://board.moparts.org/ubbthreads/show...e=0#Post8174927

Be very easy to reach that goal with the big block option. Read thread above. Simple, reliable and on pump gas.

You can achive 10's without much trouble on pump with a NA smallblock or bigblock. I see alot of A-bodies with the smallblock strokers running 10's and streetable. And of course it would be no problem with a bigblock either. If you dont have a preference of big or small block start pricing the parts and see which is cheaper. As for suspension you dont have to spend a ton. My suspension is all stock other then SS springs and 90/10 shocks up front and it hooks ok for a street car running 10's with a 1.50 sixty ft. Course you cant go wrong with Cal Tracs but they will cost more if you use the Mono spring which they say works the best with them. Ron

I have a 71 Demon with a 440...There are not a lot of Demons around..so I would go with a stroker small block and aluminum heads.

I think I would get new headers,upgrade the suspension and sticky tires and try what you have first.

I would build a solid 400 + cube(big as is practical) smallblock shortblock, run the heads you have and a single plane intake and the proper cam and see what happens! Then you could upgrade heads if you need to. There are a number of head options, but with some porting on the stockers, you might make your goal.
for rear suspension SS springs would work, but will require some good adjustable shocks to control them. Box the spring pads. I rolled mine over years ago

Thanks for all the responses. I still will consider both options and keep my eyes open for some deals when I have some cash in my wallet.
Hopefully ill realize the completion before I retire, lol

Big block will get you there easier, at less RPM and with less "exotic" parts. Using the 400 block you have some stroker options 451/470/499/512. A relatively basic build with just about any aluminum head shouldn't have a problem cracking into the 10's

It can of course be done with a small block as well, but might require a couple extras, Ported heads vs Non ported Big block heads for example.

If I was in your shoes, first thing I would do would be make the car run and drive again with the 340 you already have. Good Luck!

Brian at IMM in Indio Ca does some great things with new iron heads, might be worth a call to find out what could be built power wise.

Option 1 IMO. How do you feel about sticking a 10 pt cage in it?? - cause you are gonna have to.

You guys are right as I have a 6 point bar which is legal to 10.0. I did not want a full cage since I drive on the street so much. Ron

Also plus the roll bar its highly advised to put in
frame connectors to help keep the body straight..
plus put in the down leg bars to the frame connectors
from the main hoop at the cross bar

Don't forget that if you want to run 10's you need aftermarket axles, trans blanket, sfi balancer, etc.

I would not modify such an original car that much. I would do the 360 build, caltracs and 9" slicks and keep the car above 11.50.

I guess the big question here is; what is the point of no return ( to stock condition) without spending as much or more $ than it cost to put it in the 10's - which is why I brought up the roll bar thing. I went through this a short while back. Every situation / car is different, but IMO, you start running faster than 10.50, you are going to start looking at a dedicated race car. Even hi 10's will be starting to cross over the line. The OP needs to consider this up front, before he starts cutting and welding .