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Old Apr 9, 2011 | 11:20 AM
  #1  
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I,m currently doing an off frame resto. I,m figuring putting somewhere around $12,000 in the motor & trans which would be a 425hp crate and 5sp trans kit. My question is I,ve came across a deal on a car which has a 396 with a 4spd trans for $2500, my car is a 78. What changes would be involved in changing over to a big block? Would I eat up the savings on motor & trans making the change to a big block???
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Old Apr 9, 2011 | 01:12 PM
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Its not worth doing for a 396.
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Old Apr 9, 2011 | 01:56 PM
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You can build a heck of an engine for what you've budgeted. As an example, I just sold a 509 to a guy for $6500 - 625 hp. Find the right builder and you will still have $ in your pocket when you're done.

Other things you would need are accessory brackets and pulleys for a big block corvette. You may or may not need an aftermarket hood depending upon your intake and air cleaner choice. That's about it.

Last edited by Ben Lurkin; Apr 9, 2011 at 03:33 PM. Reason: more info
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Old Apr 9, 2011 | 03:35 PM
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Originally Posted by Ben Lurkin
You can build a heck of an engine for what you've budgeted. As an example, I just sold a 509 to a guy for $6500 - 625 hp. Find the right builder and you will still have $ in your pocket when you're done.
The 12,000 was for motor and trans, the trans is a change over kit from auto to manual which is about 4,500. The engine is about as you said 6,500. Plus allowing a couple thousand for aluminum radiator, electric fans, and incidentals. Soooo the 2 grand will be spent on both. The other 10,000 minus 2,500 leaves me with 7,500. Can I rebuild the 396 to put out around 425-450, possibly rebuild the 4spd, new clutch, accessory brakets for the big block and the other unforseens that I havent thought of for around 4,000. Because I dont want to tackle this if I cant save around 3,000.????????
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Old Apr 9, 2011 | 03:47 PM
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Originally Posted by GT's 78
The 12,000 was for motor and trans, the trans is a change over kit from auto to manual which is about 4,500. The engine is about as you said 6,500. Plus allowing a couple thousand for aluminum radiator, electric fans, and incidentals. Soooo the 2 grand will be spent on both. The other 10,000 minus 2,500 leaves me with 7,500. Can I rebuild the 396 to put out around 425-450, possibly rebuild the 4spd, new clutch, accessory brakets for the big block and the other unforseens that I havent thought of for around 4,000. Because I dont want to tackle this if I cant save around 3,000.????????
Understood.

A 396 is more expensive to build than a 454! I've found rebuildable 454 cores for $600-$750. Depending upon your wishes, you could build a 450 hp 454 for something like $4000 using the factory oval heads. It all depends upon what you want and what you want to spend. A 496 can be built for a bit more than this. If you don't want all the expense of going to a big block, I've built, and there are several people on this board who are running 406's that will eat most any factory 427/454's.

Check your private messages. I'll give you a few sources if you like.
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Old Apr 10, 2011 | 03:38 PM
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www.vortecproperformance.com

If you have $7500 you can spend on the engine, that is JUST enough for a 650hp 496" with a hyd roller, all american forged parts and dynoed....


I have one and its a great engine, enough power for 10 sec 1/4s yet cruises around nicely with AC blasting.... I've got right at 6000 miles on mine now....runs like a swiss watch...
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Old Apr 10, 2011 | 11:06 PM
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Originally Posted by ajrothm
www.vortecproperformance.com

If you have $7500 you can spend on the engine, that is JUST enough for a 650hp 496" with a hyd roller, all american forged parts and dynoed....


I have one and its a great engine, enough power for 10 sec 1/4s yet cruises around nicely with AC blasting.... I've got right at 6000 miles on mine now....runs like a swiss watch...
Do you know what your engine specs are ajrothm?
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Old Apr 11, 2011 | 04:36 PM
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Originally Posted by Ben Lurkin
Do you know what your engine specs are ajrothm?

Yeah for the most part, what do you want to know?

Ported 049 oval ports.... good port 323cfm, bad ports 3teens cfm
Isky HYD roller, 238/248*, .578/.608", 110 lsa(billet core)
1.75 Intake roller rockers, 1.70 exh RRs
Morel Sportsman hyd roller lifters
Isky tool room single w/dampener springs, 185# closed/400# open
10.0-1 compression
Mahle 9.8-1 forged/coated small dome pistons, 4.31"
Scat 4340 I beam rods
Scat 4340 Steel crank 4.25" stroke
Square decked/zero decked
balanced within .5 gram
Moroso 20403 6qt pan (running 5.5 qts)
Box stock RPM air gap intake

Not to mention all of the other Mark Jones voo doo he puts in his engines....no telling what all other machining tricks are in this thing....he spends a LOT of time maching/balancing everything himself.
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Old Apr 12, 2011 | 01:53 AM
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Originally Posted by ajrothm
Yeah for the most part, what do you want to know?

Ported 049 oval ports.... good port 323cfm, bad ports 3teens cfm
Isky HYD roller, 238/248*, .578/.608", 110 lsa(billet core)
1.75 Intake roller rockers, 1.70 exh RRs
Morel Sportsman hyd roller lifters
Isky tool room single w/dampener springs, 185# closed/400# open
10.0-1 compression
Mahle 9.8-1 forged/coated small dome pistons, 4.31"
Scat 4340 I beam rods
Scat 4340 Steel crank 4.25" stroke
Square decked/zero decked
balanced within .5 gram
Moroso 20403 6qt pan (running 5.5 qts)
Box stock RPM air gap intake

Not to mention all of the other Mark Jones voo doo he puts in his engines....no telling what all other machining tricks are in this thing....he spends a LOT of time maching/balancing everything himself.
Curious mostly. No doubt he does a great job. I've followed some of his stuff on the Chevelles board. I'm still amazed he gets those kind of flow #'s and hp out 049 style heads. I had a set of 820's ported some years ago for my LS5 454. They ended up in the mid 290 cfm range - some $800 later in 1992.

Good value ($/hp) from that guy.
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Old Apr 12, 2011 | 06:14 AM
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If I was doing a big block with an extra 100 lbs hanging over the front axle, would be more than a 396. Been in a couple well built 406 small block's that would take on just about anything, and just drop right in.
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