1980ish Mirada build

[Shorty Thompson]

Okay , It's time to start posting somethings that I've been up to . The Mirada build is what I've been up to .

Thus far the acquisition

Thus far , it's got a really tired teen where a leaning tower of power used to be . So ! you know that trans shift gate is messed up . So ,,,,, to get things running in the right direction , I started building a high school dream . I'm putting a 360 crank into a teen , fair size bump stick , better than stock heads , that's still stock , last night I picked up a nearly complete 8 3/4 out of a '68 Dodge Charger with leaf springs still attached .

 

[Joe12459]

Sounds like a sweet build!

 

[80 Aspen RT]

Looks like a great starting point.

 

[Shorty Thompson]

Just dropped off the crank at the machinist's tonight . 318 with a 360 crank . Block's .040 over . Should net me cubes in the 355 range . Shooting for a realistic HP of 300-400 HPs .

 

[Shorty Thompson]

Picked these up Last Thursday ;

 

[jasperjacko]

you don't want those heads, you should send them to me.

 

[old yellow 78]

Thus far the acquisition

That is one nice looking Mirada. They are SO unusual, I haven't seen one on the street for several years. Even the Aspen/Volare's are more common than these. Really like the colors.

 

[kkritsilas]

I have had two. Part of them not being very common, means that they are still pretty cheap. I had two (one now), each of which I bought for $CAN500 or less. I have since sold the blue 1982 Mirada base off, but replaced it with a 1980 Cordoba Crown and a 1981 Mirada CMX, both of which are higher option content cars. The Cordoba was $CAN800. THe two cars that I have now are 318-4BBL cars, and have less rust than the Mirada I wold off' they alos have less mileage on them.

 

[89.Fifth]

360 crank in a 318 makes... a 345? I think. How are you gonna handle pistons? I think Gen3 Hemi pistons will get you close.

 

[Steve2961]

Hey, just a question. Why pay to have the mains turned down on the 360 crank so they fit the 318 block rather than build a 360?

I'm the first to admit I don't know everything so that's why I'm asking. Is there a benefit to the smaller bore and longer stroke that's worth the expense of the machine work?

 

[Shorty Thompson]

Hey, just a question. Why pay to have the mains turned down on the 360 crank so they fit the 318 block rather than build a 360?

I'm the first to admit I don't know everything so that's why I'm asking. Is there a benefit to the smaller bore and longer stroke that's worth the expense of the machine work?

Simple . It was my high school dream build . Now that I can afford to do it . I'm doing it . The other reason is that a local said it could not be done . They said they tried it and shattered/scattered the crank . Now then . Not wanting to throw money down the drain I enlisted the help & guidance of Damon Kuhn . He told me exactly how to go about it . So I am . My machinist here looked at me right off with a major amount of concern on his face and looked at the numbers . Needless to say , he was concerned . I then told him what Damon told me , he reran the numbers and we're doing it . My other build was to put a 318 crank in a 360 , however since they don't make the shims anymore that build was halted dead in it's tracks . Next will be a 500-600 horse 408 . That'll be a build later on though.

 

[MiradaMegacab]

Nice build! Here's some info on the main spacers.....

 

[Steve2961]

Simple . It was my high school dream build . Now that I can afford to do it . I'm doing it . The other reason is that a local said it could not be done . They said they tried it and shattered/scattered the crank . Now then . Not wanting to throw money down the drain I enlisted the help & guidance of Damon Kuhn . He told me exactly how to go about it . So I am . My machinist here looked at me right off with a major amount of concern on his face and looked at the numbers . Needless to say , he was concerned . I then told him what Damon told me , he reran the numbers and we're doing it . My other build was to put a 318 crank in a 360 , however since they don't make the shims anymore that build was halted dead in it's tracks . Next will be a 500-600 horse 408 . That'll be a build later on though.

Cool. I can completely respect that and hope it all works out as planned. I really enjoy seeing builds that aren't common and this one fill that bill. Keep us posted so we know how it turns out.

 

[Shorty Thompson]

Thanks Y'all . Make me feel at home , kinda .

 

[Shorty Thompson]

360 crank in a 318 makes... a 345? I think. How are you gonna handle pistons? I think Gen3 Hemi pistons will get you close.

@ .040 makes it a 355

 

[Shorty Thompson]

Nice build! Here's some info on the main spacers.....View attachment 18910

I just typed in the url address , and it came up out of service . If you have a current url let me know , okay !

 

[Shorty Thompson]

360 crank in a 318 makes... a 345? I think. How are you gonna handle pistons? I think Gen3 Hemi pistons will get you close.

Silvolite 1278 pistons . They have thicker tops and can be milled down . I was concerned about this too ! Then after talking to Damon he told how to go about it . Otherwise it would be a disaster with the first turn of the crankshaft .

 

[MiradaMegacab]

I just typed in the url address , and it came up out of service . If you have a current url let me know , okay !

Shorty, you're gonna have to call Bill. IDK if that # is still in service as that post was from 2009.
I run a K1 3.79 Stroke crank that has 2.1 chevy rod journals, with a longer K1 6.125 rod again with a chevy .927 pin. This let me use off the shelf Diamond forged pistons from a 383 chevy.
You're on the right path with the 1278 pistons. You can cross reference a piston with the same CH (Compression Height) for a different application. Race Tech pistons let's you change CH with an off the shelf piston, at no additional charge.

 

[89.Fifth]

Shorty, you're gonna have to call Bill. IDK if that # is still in service as that post was from 2009.
I run a K1 3.79 Stroke crank that has 2.1 chevy rod journals, with a longer K1 6.125 rod again with a chevy .927 pin. This let me use off the shelf Diamond forged pistons from a 383 chevy.
You're on the right path with the 1278 pistons. You can cross reference a piston with the same CH (Compression Height) for a different application. Race Tech pistons let's you change CH with an off the shelf piston, at no additional charge.

Hey can you post exactly what parts and part numbers you bought? I'd love to hear more details about what you did. Been thinking about this too. Thanks!

 

[Shorty Thompson]

Parts ? Silvolite 1278 pistons , Stock 360 crankshaft turned to the 318's specs . Using stock rods . Went with aftermarket balancer from Summit , bought 2 actually . At first I was going to balance the crank , but found that way too expensive at this point in time . Finding a 70's era block was kinda tricky too , but the engine only cost me $125.