1 Bad Mirada

mark, i would bet that the stock pistons are still "flat", they are probably dished.

lear, im unsure of your explanation of the cam...292 degree...do you mean 292 duration? duration is measured in degrees of crank rotation, so i assume that is what you mean, but maybe im off base and im just not familiar with the term?

in the mirada, im running the mopar 528/284, with a 3500 stall and 4.56s...shifting around 6700rpm, trapping right around the shift point. the power range for that cam is like 3300-6800, i believe.

keep in mind though, with the big block, you start off with a substantial torque advantage over most small blocks...so for you go to to an intake that likes the top end, you lose less torque by percentage than would i with my little 340...i HATED the dual plane (mopar M1) on the mirada, and quickly changed to the edelbrock air gap, and i love that intake. the edelbrock ld340 is suposed to rival the air gap for the small block mopars, and i had one laying around, so the demon has the ld340 over a 509/294 cam, 2800 stall, and 3.91 gears.

lear4406

Ah yes the air gap is the intake I wanted and really like what I hear about it. Yeah the cam specks are for 292 degrees of duration 488 lift. Trying to keep it streetable I have run a 304 degrees of duration on my first 340 engine and it worked well with a 4-speed. I later put this engine in my Challenger with a stock automatic and it was flat on the bottom. Just terrible. I then learned after reading and talking alot that the problem with a street built engine is you want power and it to be streetable. So with an automatic you need stall and high lift short duration on the cam. That is the cam that is in there now. I can't remeber the duration but the lift was 448. And this cam made ample power, just not enough in the upper RPMs. 5500 rpm was about it. I too have a small block and to hear you talk about the airgap makes me wonder if I should spend the money now and buy one. I am looking for more RPM. Around 6500-7000. My compression is 10:1 with the heads shaved ten thousanths. I'm using the 2.02 and 1.60 valves with back facing and a ported intake and exhaust. You are using a solid lift cam?

1 Bad Mirada

youre running a small block? interesting.

with the mirada, im running a 69 340, 30 over, stock stroke (right now). bg 750 with 800 cfm proform carb, air gap with the 528/284 cam, 1988 360 heads, ported and polished, 1.88/1.60 valves, 1.5 ratio roller rockers, solid lifters. 100 thousandths dish pistons, 9 to 1 compression with the heads shaved. running only 87 octane, it ran 12.30s-12.40s, track weight of 3700lbs.

the demon is going to be a 1975 360 (dont tell anyone ), stock bore and stroke. 750 holley, ld340 with the 509/292 cam, 1973 340 heads, 1.88/1.60, stock 273 adjustable rockers, solid lifters. stock pistons and everything else on the bottom end. stock it was 8.4 to 1, but the heads that im running are shaved and im running the extra thin head gaskets, so the compression should be similar to the mirada. the demon is a total budget build. the most expensive thing we have bought so far was the OEM wiring harness.
im not sure on the weight yet, but its got a fiberglass front end, clean trunk, lightweight interior...so it may be several hundred pounds lighter than the mirada. i believe that the stock demon 340 weight was around 3300lbs(ive seen numbers that vary from 3250-3350), so it could be under 3000lbs. that would be awesome...real awesome. we still havent thrown out the idea of the mirada drivetrain in the demon. figure, the 3700lb mirada went 12.30s, and the demon might weigh 800lbs less? mid 11s would be nice...

lear4406

Nice combo and from an old school guy... interesting choice. Your combination works real well. I'm a product of the 70s and with us bigger was always better But as I have been seeing a better approch such as yours with the matching of parts and R&D yeilds great results. I use the 2.02 valves and 1.60 exhaust. You are getting great results from the 1.88s. Lower compression and using lower octane. Your times are really good. I keep adding things to my combination so I'm not sure what it will be as an end result. I hope it won't fall on its face I'm now looking at steel 1.6 roller tip rockers. I love A bodies and can't wait to see your results from the Demon in the 1/4 and I swear I won't tell anyone your running a 360... just between you and me Did you see Hot Rod Mags crate motor coverage on the Chrysler LA 440 small block? 540HP nice and better was the torque. I would say if asked... yeah its a 318

1 Bad Mirada

a friend of mine has a demon with one of those 440 small blocks..he drives it to car shows, and it runs low 9s...[&:]

i also run about 50 degrees advance timing in the mirada...bat that one around a bit...

a few years ago, i ran out of gas on the return road, and coasted to the pits, and got a push from a guy i raced with..i was so angry i stopped the car next to the generator, and pulled the fuel feed line off, drained it into a gas can, and poured it into the car. the guy who pushed it said "you cant put that cheap gas on the mirada!" it ran like a 12.65 the next run.

it really is an odd combo, and i think that when i explain my setup to many people, they think that im full of it. the mirada will be slightly more wicked once its fixed. the new bottom end has 13 to 1 pistons and a different crank...although that would destroy my ability to run cheap gas...and that compression will cause more heat. my combo runs so cool, that on an 80 degree day, i can hot lap three runs without turning on the water pump or fans. we have thought about going with the small stroker kit that i already have, and keeping the low compression pistons.

someday i will get a nice set of aluminum heads, but for now, i like peoples reactions to "i run stock truck heads and run low 12s"...

out of the box, we would like the demon to run in the 13s, as we are running what i consider to be a pretty conservative setup.

i would really like to make a modern take on a mr norms GSS demon...that low compression 360 would probably eat up some forced induction...but for now, its a budget build. im keeping close track of what we spend, and im going to write about it...and it goes to show that you dont need 50 grand to have a nice, reliable muscle car.

here is a video that is a few years old, of me racing amanda...the weather was awful that weekend, and my setup just wasnt working, but a few weeks later, the truck got into the 14.80s, and the mirada got into the 12.50s, then later that season in cool weather, it ran 12.40s and one 12.39...it broke first run out of the box the following season.
http://youtube.com/watch?v=H1cxSQhLJX4

and an exhaust video with the aforementioned setup.
http://youtube.com/watch?v=uA1rYV2HA6Q

lear4406

Again I'm giving you a thumbs up on your choice of engine parts. Seems your going in my direction now 13:1 . I will be waiting to see your results in 1/4 and I think it will be quick. Lighter and more to the combinations I'm used to seeing.

1 Bad Mirada

my knowledge in engine building is rooted in my dads experience...and hes been putting together mopars since the 60s, when the guy who owned the dealership where he worked would say to my dad on a friday night "throw logos on a new hemi car and take it to the track tonight"..so my dad would put these huge magnets with the dealer name on the side, and take brand new performance cars to the track to race!

ive put together turbo 4s, Na small engines, but im most comfortable with carbed V8s...even compared to things like amandas 94 fuel injected ram...i can tune the mirada with a screwdriver...and i hear kids at the track complaining because their laptop wont power up, so they cant tune their car...

lear4406

Thats funny Because I'm looking at a stand alone system for my Conquest. Speaking of my Conquest... I got the rebuilt alt. on it today and took it for a spin. Man that little car pulls hard past 7000 RPM. And thats on 8lbs of boost. But with the cam and bigger turbo, I need a way to tune it. I might just for the time being use an SAFC to tune it for the factory ECU. Man I would love to sit down and talk to you and your father about racing. I bet your dad has some interesting stories to tell and to hear them about Mopars would be cool. Bench racing is one of my favorite sports. If they have a big Mopar meet up your way or Charlotte has a big event we could get together and talk shop.

1 Bad Mirada

you really should make it up to the mopar nationals in columbus...there were several spotless conquests there two years ago. there may have been some last year, but i sustained an eye injury at the event,and was only really there for one day.

lear4406

I will see if the nationals are in my time frame between outages. I'd love to drive up and see all the action. I went years ago with the Mopar Muscle Club to the Mopar Nationals in Indy. 1984 I believe. I drove my GTX. Had a blast and saw some awsome hardware. I'd be up for a trip like that. Also my sons love cars and own Mopars of their own. I think I see a road trip