lowcountry

iTrader: (1)

When my 70 Z28 gets out of the body shop I will be purchasing an LS7 crate engine to put in it. The plan all along has been to go with a GM crate "505 HP" The body shop is taking longer than expected - giving me more time to research LS crate engines (not necessarily a blessing).


This will be a street car and my main concern is durability. I know increased power usually is inversely proportional to longevity - the initial reason I chose a GM LS7, and "505 HP" is a substantial amount for a street engine... But, for a couple of grand more, I can get a Mast LS7 SS with 650 HP with claims of durability similar to the GM. Mast has an 18 month warranty - forgot what GM's is.


I have done some research on Mast - mostly good - some bad.


Any comments/experiences on this subject? A 150 HP is a lot to give up all else being equal...


thanks

KW Baraka

iTrader: (7)

I believe the GM LS7 will come with a 24 month warranty. A very smooth operating engine; almost a sleeper, depending on your exhaust.

The Mast engine will, in no way, be a sleeper. It's a mean performer and everyone with 100 yards will know that 'something' is on the way. PERIOD!

If you have the money to spend and don't mind being noticed, get the Mast. If you want to fly under the radar.....go with the GM engine.

IMHO ....

KW

1sick_eg

Mast heads would certainly help me sleep better vs. the factory ls7 heads.

lowcountry

iTrader: (1)

Thanks for the replies.


"It's a mean performer and everyone with 100 yards will know that 'something' is on the way"


I like the way you put that...


Thanks for the feedback. Trying to figure out if the Mast engine will be as dependable given the extra HP. Also, I'm unfamiliar with the computer aspects of both engines and tuning and such - Mast has their own software...I have no experience with computer-controlled engines. Carbs have their own inherent tuning which I finally mastered before switching over...

KiwiKid

Its a no brainer, for a couple of grand more I would go with the Mast engine, at least its got steel rods and forged piston's, and its semi blue printed so that's a lot better than taking a gamble with the factory build tolerances that you could drive a horse and buggy through!

Cheers,

Mark.

uxojerry

Anyone with a factory LS7, spends around $4k to get the heads reworked due to valve guide issues. For your purposes, I would consider the LSX 454. Pace sells a turn key 454 intake to pan and all wiring for $14k.

FLYZNTN

I'd go the aftermarket route.

You'll spend a little more but, with the aftermarket heads, valve guide wear will not be a concern.

TSP 427

If you can find one that has been re-sleeved I'd consider that as well. The stock sleeves on the LS7 have been known to crack. Ductile iron eliminates that issue.

The sleeve issue, however, from what I have heard, have been mostly in power adder applications so, for you, the stock ones would probably be fine.

Having said this, please don't take my opinion as gospel. Anything that I convey, on the LS7 front, is based solely on what I have read over the years. I've never actually run or built one. I have gone as far as buying a 5.3 block but ended up not using it. I actually gave the block to Tick Performance and last I heard they are racing it (as a 5.3).

I did a LOT of research on this though. In the end, for me, the reason I didn't go to a 427 is because I didn't have enough blower...... FWIW.

slogo

At least consider this option, get his short block then get you some good heads

http://www.erlperformance.com/produc...locks-domestic

Project GatTagO

iTrader: (7)

The GM LS7 is also dry sump and has titanium rods (good, bad, or indifferent)...

As far as I can tell most aftermarket LS7s are not based on the LS7 block but are really stroked LS3 block based engines. Big difference...

Andrew

gnx7

iTrader: (28)

You can get an LSA or zl1 pullout for under $10k. Add $1k in mods (pulley/air filter, tune) and you have 650hp/600tq+ and that's with a stock baby cam in it.