Generation IV Internal Engine - 427 versus 408

Trying to justify to myself building a 427 is worth the extra $$$ over a 408. LS7 style heads look to flow better than 4 inch bore versions but question is how much power is really there to be had.

Not looking for a drag engine, something that can be driven a lot in F body and put down 550 or so RWHP, have good street manners, be reliable and accept a little N2O at track.

Lastly, anyone using Lunati rotating assembly in a 427? Have had good experience with Lunati in BBC's, looking for LS feedback.

What block are planning to use on 408ci or 427ci?? aluminum or Iron??

From those engine Id choose none LOL Go with LS3 418ci with the right cam/heads/intake will get you 550rwhp for sure and you can spray the car too and the price is awesome too..

is your car an M6 or auto?

Lunati is a great rotating assembly but expensive I used Wiseco pistons and Callies Rods and crankshaft in a couple of builds they're awesome and great price too.


GOOD LUCK

Trying to justify to myself building a 427 is worth the extra $$$ over a 408. LS7 style heads look to flow better than 4 inch bore versions but question is how much power is really there to be had.

Not looking for a drag engine, something that can be driven a lot in F body and put down 550 or so RWHP, have good street manners, be reliable and accept a little N2O at track.

Lastly, anyone using Lunati rotating assembly in a 427? Have had good experience with Lunati in BBC's, looking for LS feedback.

If you're gonna use LS7 heads...those suckers can breath. You'll want as many cubes as possible. There are ported LS7 headed/ported LS7 intake 427's making 580 RWHP and daily drivers.

Call Katech, I remember they had some Cola cranks laying around they were trying to sell awhile back. Perhaps one of the best crankshafts ever made. Not sure what strokes they were though.

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As for block, trying to decide between LSX iron or Darton MID sleeved LS1. Neither is what I would consider cheap but both appear very durable.

Lunati has a solid reputation and I believe still forges in USA. Guess you get what you pay for.

Car is M6.

Why not go with a resleeved ls2?

As for block, trying to decide between LSX iron or Darton MID sleeved LS1. Neither is what I would consider cheap but both appear very durable.

Lunati has a solid reputation and I believe still forges in USA. Guess you get what you pay for.

Car is M6.

I would get the LSx and do a 454 with ported LS7 heads, that will get you 600 rwhp no sweat for a daily driver, plus you could still hit it with 150 or 200 shot at the track.

I would only do the sleeved ls1 if weight is an issue, and right now morris motorsports is selling ERL sleeved LS2 427 shortblocks 5000, 4500 if you can exchange either a LS2 or LS3 block.

sheesh wish i could throw 5K on a shortblock...and if you are looking for mid 500rwhp what do you plan on doing with your trans? my suggestion is call Joey at tick performance

Will LS7 heads fit on a 418?

If your looking to spray then a 4" stroke would be better. The 408 will make the 550 just as the 427 but the bigger cubes should allow for a smaller cam and better drivability.

The rest is all about budget but a big heavy Lunati crank isn't the best choice here. If you have to have an American forged engine then we go to the Dragon Slayer and Carrillo rods. I would go with a re-sleeved LS2 as well an save the weight on the block too.

I have been doing a lot of searching this and other sites regarding sleeving. What I have found so far appears to support that the Darton MID sleeved LS1 block with wet sleeves is more durable than a dry sleeved LS2/3 or LS7 block.

As not everything you find on net is accurate, would appreciate any further feedback.

Pricing I have found so far is that wet sleeve version costs more but if I have to purchase a LS2 block overall cost is about the same. (have a LS1 block)

Appears consensus so far is the LS7 heads are worth the difference - especially if can run a smaller cam with better drivabilty.

If you have to have an American forged engine then we go to the Dragon Slayer and Carrillo rods.

Carillo rods, yep.

Dragon Slayer crank is not an American forging. It's a good crank and finished here, but not forged in the USA.

Call Katech, I remember they had some Cola cranks laying around they were trying to sell awhile back. Perhaps one of the best crankshafts ever made. Not sure what strokes they were though.

4" Cola crank (from Katech), Callies Compstar rods and Diamond pistons in an LS7 case here. An LS2 sleeved would be o.k. too.

The LSX case was too heavy for my application.

Carillo rods, yep.

Dragon Slayer crank is not an American forging. It's a good crank and finished here, but not forged in the USA. You sure about that ;) The Compstar is forged overseas
DragonSlayer crankshafts are made in the U.S.A. for American Racers. Our LS1 crankshafts are machined from premium 4340 forgings.

Compstar Crankshafts are a great value for the budget minded racer or high performance street enthusiast. These cranks are designed by our engineers, and rough machined to our specification on 4340 material forgings overseas.

Thanks for tip on Tick Performance - looks like a great firm.

4" Cola crank (from Katech), Callies Compstar rods and Diamond pistons in an LS7 case here. An LS2 sleeved would be o.k. too.

The LSX case was too heavy for my application.

Do you knwo if they still have some 4" Cola's?


Must be fine with a fast luxury car.........

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I would go 427ci. I have a 402ci a cola crank from ktech and callies rotating assemb w/ported l92's stock l76 in a m6 car. 520hp. with the new fast ported,i should get 540hp from it. a 427 should gain even more .