Short Block or Crate engine?

[Guest z31_drifter]

Okay I could do that too. Would be cheaper that way probably too. I know that a LT-1 is a short block, I knew what I meant when I said that. I meant LT-1 or 350ci.

[Tim240z]

LT1 is a 350ci sbc..

[Guest z31_drifter]

LOL. My bad!! What I meant is an LT-1 or a crate engine. I hope you knew what I meant.

[Michael]

Finding a “donor†engine and doing a complete rebuild is the most educational route, but probably not the cheapest. And definitely not the shortest.

 

I bought a used 454, originally out of a 1978 Chevy Suburban; price: $850 (yes, big blocks are more expensive). A friend and I swapped it into my Z, with the following engine mods: new aluminum flywheel, Comp Cams hydraulic flat-tappet cam and cam kit, Performer rpm intake, Hooker block-hugger headers, Holley vacuum-secondary 750 cfm carb. The aftermarket parts I bought at Summit, some with a 10% discount that I had at the time.

 

After break-in of the cam, I drove the car for about 20 minutes – before a sharp knocking noise became apparent. I thought that it was a spun rod bearing; but in actuality it was a wiped cam.

 

Fast-forward two years; I disassembled the engine down to the bare block. Spent many, many hours porting the heads.

 

Fast-forward another year: finally got the gumption to take the block, heads, crank and rods to the machine shop.

 

$1800 later, I had a nicely machined block, reworked rods with ARP rod bolts and shiny new hypereutectic pistons, ground crank, balanced rotating assembly, – and ruined heads! The heads developed cracks when the machine shop was pressing in new valve seats.

 

Fast forward one more year: I’m still waiting for AFR to finally bring to market their long-promised 265cc oval-port BBC heads. Are you listening, AFR????

 

Now let’s see.... I did successfully recycle the block, crank, rods, and harmonic damper. I also recycled bolt-on's like water pump, starter, alternator and fuel pump. Everything else is brand new. And now let’s add up what still remains to be bought:

 

Heads (assembled) - $2000 (at least!)

Mechanical roller cam and roller lifters - $750

New head bolts - $100

Misc. gaskets (like copper head gaskets) - $100

 

So this is roughly a $7000 engine, pan to carb, with my assembly labor (and excellent help from a few folks on this site!). It should make around 500-550 ft-lbs torque, and maybe 480 hp. OK, 500 hp with an collaborative dyno. Roughly the same numbers as the ZZ502 crate engine from GMPP, which, oddly enough, is also around $7000 new. Of course, that engine has inferior valvetrain and heads, it’s set up for automatic transmission, and makes the same power numbers from about 40 cubic inches of displacement.

 

The good part is that I know exactly what’s inside that engine. No nasty surprises from unscrupulous shops or builders. But I paid for my MISTAKES, and I’m still paying for them, in money and in TIME.

 

Do you have half a decade to build an engine???

[Guest Stumppuller71]

Hey there Michael, I was just curious about what it took to get the BBC into the Z? Did you use custom mounts like an engine plate or actual chevy motor mounts? And what did you use for exhaust as far as headers was concerned? Any info would be greatly appreciated. P.S. I REALIZE THE LAST POST WAS 4 YEARS AGO BUT MICHAEL IF YOU ARE STILL AROUND PLEASE GET BACK TO ME ; )

[pparaska]

Here's an article that Michael wrote up on the swap - not for those without a welder! LoL!

 

It can be done without moving the firewall, though.

[grumpyvette]

"Fast forward one more year: I’m still waiting for AFR to finally bring to market their long-promised 265cc oval-port BBC heads. Are you listening, AFR????"

 

 

Your very un-likely to see those heads....EVER,,, simply because theres a very limited market, brodix makes some nice oval port heads if your interested,

http://www.brodix.com/heads/heads.html

 

but don,t get crazy worrying about port size.

With the correct cam and compression ratio and use of a matched intake manifold and header design even a fairly large 310-315cc big block rectangle port head can make killer power and decent mid rpm torque on a 454 displacement engine.