Is Blueprinting Worth Anything on an LS

[Bazman]

Striking to the heart of engine building right here, but there's no doubt the latest couple of generation of V8's from the big 3 are built to entirely different tolerances than the old muscle car engines were. A mild bolt on big block could easily find another 50hp with a good basic blueprint beyond merely bolt on to a stock engine. But blueprinting an LS3 or 7 may be lucky to see 10hp - am I right?

What if we strengthened up what God gave us?

Let's take an LS3 build as an example:

Baseline Engine A: stock crank, mild street cam, headers, tight squish (040 gaskets) making say 430rwhp on the dyno with full accessories and exhaust and on pump gas. Stock engine with cam, gasket and exhaust and tune - 430rwhp is very common some more, some less.

Engine B: Identical but you took it apart - Add main and head studs, blue print the block - align, check parallel, fit Darton MID sleeves and retain stock bore (to compare apples to apples), aligned the lifter bores and sleeved them perfect, custom length pushrods (if necessary), super finish polish the crank and cam then stealth coat that and everything else that could use it, clean up the ports (no porting just debur and smooth out), precision balance to within +/- 2 grams, bores within 0.0002 top and bottom etc....

Engine B is same as engine A except stronger and stiffer. What would be your guess as to power? 430rwhp baseline.

Obviously the more potent Engine A is the more potential gains to be had e.g. once power adders come into play and the stock block starts to move around under pressure.

Any gains at all down as low as say 430rwhp?

[Rowdy Yates]

Very little 20 to 50??? & u r correct in theory. If FI is used you know which will hold up better without worry.

[PackardV8]

Can't fix wot ain't broke.

[Walter R. Malik]

LS3 is a good engine until it starts making some real power ... then the O.E.M. aluminum block is no better than trash.

[pamotorman]

don't the corvette engines make over 750 hp with a stock aluminum block and warranty for 36,000 miles.

[GARY C]

It would be interesting to see, John Lingenfelter was said to get 100 horse out of the mid to late corvette without changing any parts, blueprinting everything was part of it but it was never detailed as to what all he did, I am guessing there was porting involved to get those gains.

[PackardV8]

don't the corvette engines make over 750 hp with a stock aluminum block and warranty for 36,000 miles.

755 horsepower. Warranty: 3 yr/36,000 mi basic, 5 yr/60,000 mi powertrain.

[GARY C]

don't the corvette engines make over 750 hp with a stock aluminum block and warranty for 36,000 miles.

There are guys running bone stock 4.8 and 5.3 LS with over 30 lbs of boost, not sure if those are alum or iron but there running 7 second 1/4 mile times and living.

[RevTheory]

When we contacted Lingenfelter for a turbo LS3 build roughly 10 years ago, I asked them straight up what hp level started making them twitchy with aluminum blocks. He said "about 1,000 hp."

[Bazman]

Calling them trash is a tad harsh. I love the old Mopar RB440's but those blocks are trash at the power level LS3's routinely make day after day.

The LS3 is no Ford Modular in strength but they're reliable to 650rwhp on stock internals, a lot more for the odd drag race. Mine makes 663rwhp and has done week long events, several 1000kms and many dyno pulls. It needs forging to go any further, but I lean on it for miles at a time on closed twisty roads, it's never missed a beat and returns over 20mpg highway without trying. They're a good base engine for anything less than professional racing imo.

The new LT5 made 1486hp (crank) STOCK before a rod bent (caught before any damage) and that was after multiple pulls by Katech at 30+psi. The LSA and LS9 blocks have piston oil squirters, I'd assume the later LT4 and LT5 does too given they come with dry sumps. The iron LS versions are popular for cheap racers wanting cheap power and they hold big boost... but last thing I need is cast iron up front hurting turn in.

The point is has anyone seen much power gains by strengthening and blueprint work at milder power levels?

My car will road race at 700rw and not see more than 1000rw for a drag race or the rare roll on/flying km event, so most of it's WOT life will be at 700rw (can't use much more than that and keep enough fuel between stages or keep a bad smell from seeping out of the seats).

The alternative is to just go RHS or Dart LS Next alloy with MID sleeves.... but you're adding another $5-$10k that I doubt is necessary under 1000rw. I can't see why an LS3 cannot be uber reliable at 700rwhp with blueprinting, stubs and decent sleeves, piston squirters etc. Am I wrong? The Dart option is $10k with nothing in it

[Bazman]

If you had to use an LS platform (and you don't want an extra 100lb over the nose so need to use all aluminum) at what point do you forget the OEM LS block (even with MID Darton sleeves and studs) and cough up for a Dart block or perhaps the cheaper RHS?

Assume power has to be applied for sustained periods on and off so the engine must be durable and kept cool.

My thoughts are that 700-800rwhp would be very stable/durable with MID sleeves, but I've been wrong before. I think Dart would be the ticket over 1500hp for sure. In between that is grey.

Anyone else with thoughts on this? MID sleeves are common with top racers but very few talk about it.

[rebelrouser]

I hear the term blueprinting a lot, and just to get an opinion from the others on the forum, what does that really mean? blueprint and engine? Older engines were made and machined on the sloppy side from the factory, so you take the engine to a machine shop and they re-machine all the components to a tighter tolerance, so the builder gives the machinist a "blueprint" for what he wants the engine to be. If it is a performance engine you may want more piston to wall clearance, or more rod side clearance, so the builder changes the "blueprint" from stock. So the LS engine in the thread, has a much higher quality factory machining than say a 60's 327 chevy. So in the context of "blueprinting" are we talking about better machining than stock, or a different set of specs to make the engine run better? When people tell me this engine has been blueprinted, I always say to what specs and let me see the sheets, I seldom get that info from a customer.

Its like the term CNC cylinder heads, are we coping somebodies proven work of hours on a flow bench, or we just telling the CNC program to make the heads 10% bigger to get more flow. I much prefer to pay for a program that copies a good head porter, but I normally get the run around when I ask who did the original work that was copied into the program.

[rfoll]

I started understanding blueprinting when I stated measuring stock sbc stuff. Pistons .030-.040 in the hole on one side, and .045-.055 on the other. Rod and piston assemblies weighing 20-30 grams different high to low in the same engine, etc. I suspect such variances are a thing of the past.

[PackardV8]

Same with con rod length. The bad old days new SBC rods would vary .004" - .006" in length. Most SBC cores coming in now have already been through at least once; if the rods were reconned, they'll often vary .006" - .010" in length. A virgin LS core will have rods exactly the same length.

[Bazman]

All good points. If the block is already fairly square, parts made and fitted accurately and the motor pretty well balanced,the gains to be had are small. Checking tolerances etc while still valid, the accuracy required to improve now is pretty fine and the gains small without modifying the motor.

But there are gains to be had e.g. A guy on the LS forums found a 070 variation in pushrod length required to get an even 040 preload (hyd roller with Johnston ST lifters)

Nevertheless I think it'd take some skill and super accuracy/finishing to improve on OEM anymore than 20hp on a stock LS3, even by adding sleeves and studs - without porting and power mods.

As said above, once power levels rise beyond 600-700 it's a different ball game and the "black magic" opportunities come into their own

My own unqualified expectations are that I could see a 50hp difference possible by 700-800rwhp between a modified block and a stock one if you averaged several heat soaked pulls (LS motors detune themselves with heat which explains why some make big dyno numbers then can't back it up once hot on the track). I also suspect that under 1000hp an aftermarket block won't make any more power than a modified sleeved stock one - 10/15 at most. Above 1000hp then the difference should increase. Plenty of factory castings well over that, but no doubt they'd last longer and make more power with a top shelf block.

Some of you guys that have played with them like Steve Morris and Ken McCaul at Borowski would be better placed to comment on where the cut-off was than my feeble research indicates