454 LS6 Build
 

Follow along on this SHP 454 build and the Blueprinting process. All main parts have been selected, have arrived and are at the machine shop. Should be done in a couple weeks. Jeff has 5 454 builds underway at once now.

Thanks to many of you for your help and advice.
Will be dyno'd when complete.
FWIW this is a period correct engine, not number matching.
More specs and pictures available if interest warrants.

More pics:
https://www.corvetteforum.com/g/album/12663307


https://cimg1.ibsrv.net/gimg/www.cor...acddee6465.jpg

Should be an excellent engine

My Component selection criteria:
Orignal LS6 components, look, and driving characteristics. Period-correct appearing parts, non date matching. Solid Lifter Camshaft. Torque and power and rev-a-bility
Decent idle, 12 in vacuum at 800-900 idle, great sound, low end torque, linear horsepower climb, 6000-6500 rpm peak HP, 7000 possible w/o damage

Desktop Dyno predicted results: LS5 like torque below 2000 rpm, near 400 lb at idle, over 500 by 2000, 579 peak at 4000

Let's play a guessing game:
Peak HP at 6000-6200...any guesses?

SUB'D for updates.

074 is essentially an iron rectangle head made out of aluminum, but much easier to do port work. And we dont have cam specs. So, 450 to 550.

Nice guess!

Cam specs:
Sig Erson Custom Solid Lifter 274/282 238/246 .585/.585 110 LC
Dyno simulation says 555HP @6000 579lb tq @4000 over 500lb @2000 Hopefully the real dyno readings are close!

Numbers should be close to:
555 Gross HP on an engine stand dyno
485 HP at flywheel in car
412 RWHP at rear wheels on a chassis dyno
https://cimg6.ibsrv.net/gimg/www.cor...ae699c8eaa.jpg

My friend Jeff is a meticulous machinist. He's been doing these old school SBC and BBC for 40 years, mainly for racing. He's trying to sell his shop and retire soon, so that's why I am starting my Vette restore with the engine, not the other way around. We are incorporating quite a few racing tricks into the build to help the power output. So maybe the Desktop Dyno prediction will be close rather than optimistic. He guesstimates 530 but usually over delivers. I thought you might want to follow along and watch an old school artist of a machinist at work. He said it has been a long time since he built a BBC that didn't runs 10s or faster, so I have to keep his enthusiasm in check, not the other way around! His son's 650 cu. in. BBC (Merlin) just dyno'd at 950HP!

Block selection:
This our 3rd or 4th block. The one in my car was a 2 bolt from 1979, not number matching, already bored at least .030 and deemed not acceptable for this build. It seemed like it might be a fresher build, but it sat 20 years. The cam is unknown, the build quality/ pistons are unknown, and one cam lobe is wiped, etc. So it'll come out. I could have done a mild build up on that block, but this is my once in a lifetime dream car, so....it's out.
https://cimg1.ibsrv.net/gimg/www.cor...579185fd73.jpg

I'll keep the chrome jewlery.

Block Selection:
I searched the country, and found 2 matching number blocks, one was even a factory '72 4 bolt.The $1700-2600 price tag was just not worthwhile for a non-matching numbers car, as they didn't even make LS6s in 72. I did find an OEM 1970 LS6 with aluminum heads that I almost bought, it seemed good but was a 12.5 CR motor. It was $5000 or so but needed all gone thru and it used to be a race motor, so you never know what you are gonna get there. And I know the heads had been ported to within an inch of their life, so....Instead I browsed thru 30 of Jeff's big block cores. No matching numbers. Found a 66 396 block for him that we sold for good money. Has a 67 427 block but it is really rough. Found a code correct really thick wall 289 block that could be bored .120 for a extra big BB at 477 or 507 with a stroker. But it was a 2 bolt. Settled on one of 3 solid 4-bolts he had. A late 70s truck block and two 90s marine blocks. We cleaned up the truck block a little in the media tumbler and the bores looked too rough, and it was already .030 over. The nicest marine block had hardly any scale and cleaned up good, but during decking, we found the tiniest crack between deck and lifter valley. So that's two for the trash pile.

So the next one went into the tumbler, and it cleaned up way better than expected. It was a std bore and didn't look bad as-is. But of course we cut it .030 anyway. We could have gone .060 over right away for some more cubes, but he likes the idea of thicker cylinder walls.

https://cimg2.ibsrv.net/gimg/www.cor...3ba8b1ead5.jpg
454 Std Bore
https://cimg1.ibsrv.net/gimg/www.cor...358683d0fa.jpg
Getting set-up in the Align Boring Machine

Block Machining:
Most of the major parts have to be been selected, purchased and delivered before machining can begin. All the machine work is based on the parts selection. He really tried to talk me into a 1/4 inch stroker crank for 496 cubes. It would only be like $300 more than what I was spending anyway, since I was buying everything either new or used. I really wanted to stay with the BB car's original 454 engine size so I'll give up the extra 30-40 lbs of torque at low speed. Probably break less parts anyway! I want an old-school LS6 ride that revs like an original SHP big block should. It will make 100 ft-lbs more than my old LT-1 so I don't think I'll miss the extra torque much. He wanted to go with 1/4 inch stroker rods like a race motor, for better rod ratio, less piston friction, and more power. The piston for those also gave us a higher piston deck height which helped both the quench and the C.R. It allowed us to have 10.5 C.R. with a short 1/4 inch 27cc dome for better flame propogation and more power. All sounded good to me. Longer rods meant new rods vs reconditioned old ones, which was about the same price anyway, and a lot less labor for the old man. Then the block got decked .015 to clean up the deck and set the piston deck height. I think it is .010 down IIRC. So many notes to take and remember when a master engine builder is rattling away. Especially when the good stuff is all mixed in with old war stories and tall tales.
https://cimg7.ibsrv.net/gimg/www.cor...99aa6ea5f9.jpg
Decked .015 in. to cleanup deck, and establish desired piston height and C.R.

Block was then rough honed and final honed to set .005 piston clearance. We chose forged pistons in 2618 alloy with 1% silicon. Good tough forged piston. Wall clearance was set to .005 inch. With deck plates for for honing with stones. Honing is two step. 1st set stones at 400 IIRC for good deep grooves and oil control. Then a final cut with a smoother hone, just 2 or 3 passes to knock off the sharp high edges for better ring seal. Old racers trick. Breaks in fast, holds oil, and lasts a long time. The block was aligned hone to make sure everything is really squared up, and then the block is done. I guess the painting is gonna be my job.
https://cimg0.ibsrv.net/gimg/www.cor...06297dbc5e.jpg
Block machining completed

SHP 454 four bolt blocks already have two chamfers in the bores for valve unshrouding for extra power. I made sure I got one with those.

https://cimg9.ibsrv.net/gimg/www.cor...e7f421e2c1.jpg
Custom hone with deck plate, cylinder valve reliefs for power

Rods and Balancing:
Now Jeff is really on a roll. The 2618 Alloy pistons are the tougher of the forged alloys and what is used in race pistons. He set them at .005 cold I think. They expand a little less than the cast ones or the 4018 hi-silicon forged, so they will rattle a little bit when the engine is cold. Well isn't that what a SHP BB or SB is all about? The rattle is part of the experience. I loved that in my LT-1. It really does go away quite quickly as the engine warms up, and no it might not last 100,000 miles either. Oh well. I should be so lucky to be able to drive this SHP BB that long!

A lot of time and tender care went into the rods and pistons. First everything got weighed on a .01 "centigram" triple beam laboratory scale. I had to show them how to read it that well, they were only reading it to .1g. Close enough I guess. LOL Way better than the new parts were, as-delivered. Brand new rods and pistons were off by several grams from one to the next. Grinding with a dremel tool commenced until all rods and all pistons were within the same weight +/- 1.5 g. The rods have balance pads on them for this purpose. Then the rods were weighed on each end. Then the balance pads were ground on each end to the smallest of the available numbers. Several grams were removed from each rod to lighten them for quicker reving, I forgot the amount. Then each rod end is ground to balance all eight small rod ends and all eight big rod ends. Everything is within 1 g or 1.5 g when done. Couple of hours here, but I said Jeff was meticulous, and he is not done yet.
https://cimg5.ibsrv.net/gimg/www.cor...f22457798c.jpg
New Rods lightened to minimum and balanced both ends to under 2 g
https://cimg3.ibsrv.net/gimg/www.cor...205d9c9d00.jpg
Pistons and pins weighed and balanced to under 1g
https://cimg4.ibsrv.net/gimg/www.cor...e29b2b871d.jpg
Bronze bushed rods for less cylinder wall friction for power
https://cimg2.ibsrv.net/gimg/www.cor...b3ec8d6717.jpg
Connecting rods painstakingly weighed on each end by 0.01g lab scale Sorry those H-beam rods are not for my lowly street motor, they are for a 1000HP blower motor.

Next up is piston/rod assembly. The rods have bronze bushed small ends for less friction on the piston skirts and more power. That means they go together with spiral locks, which is actually very quick. But during assembly all the rods and pistons will be paired together with their total weights in mind, so that all the assembled rods & pistons now weigh within 1g of each other, or less.

Crank balancing:
Now that we know the final "bob" weight the crank can be balanced. I got needled again about being "cheap" and not going with a stroker crank, but we are way past that point now. Jeff had several GM steel cranks laying around since so many of his race customers are going to stroker cranks. We picked a good one, that was maybe .010 under, and had it polished and balanced to my pistons. That adds power too. It sure takes a long time to build a motor this way. So many meticulous steps. But if each one of these "special touches" adds only maybe 6-8 HP, and we do a dozen or so of them, hmmmmmm.... Now we are talking! That's the difference in a blue-printed motor vs just a rebuild.

Jeff keeps busting on me about spending near $9k on this thing, when he swears he could make way more power than that for almost half the money. But I just keep telling him, then it wouldn't really be an LS6 anymore, it be just a 650HP big block. That's not a bad thing, at all, it's just not the end result I have in mind. I found out a long time ago if you build an image of the completed car in your head, before you begin, then you will not be detoured by a thousand little decisions that pop up as you move along.

More pictures to come after I visit today.

My little street engine has plenty of company at the shop. This one is his "Big Brother" 640 cu.in. 1000 HP Hmmm.... looks complete...should bolt in....slight hood issues
https://cimg2.ibsrv.net/gimg/www.cor...4cedaed27a.jpg

Looks nice...keep at it.

One thing I've always done is to drill this hole in the cam thrust area. It puts oil to back of cam so it doesn't chew up the block like so many do. No loss of oil pressure because cam is rotating against the hole. Will save the block forever.

JIM

https://cimg2.ibsrv.net/gimg/www.cor...83eec432cd.jpg

Ok the 76 lb forged steel crank is in place in it's new home. If you look closely on the leftmost counterweight, you can see the two new fresh drill holes left over from the balancing. The new rods & pistons are 130 grams each lighter than stock, and you can see how much material had to be removed. These holes are also present on the other end counterweight. 130 g x 8 yields about a 2 lb weight loss! All that lighter reciprocating weight yields more power. In reality it's only about a 10% weight reduction. Each piston weighs 598 g and each rod weighs 862g. So they are definately hefty. Each rod weighs almost 2 lbs and each piston 1 lb. Does anyone else think it ironic that 454 grams = exactly 1 pound? Anyone else curious how many pounds of steel are spinning around in these things?
https://cimg2.ibsrv.net/gimg/www.cor...443d5a796d.jpg

The crankshaft is a 7416 casting which was used in 70 LS6 Chevelles. But also in truck motors and marine motors thruout the 80s and even the 90s.
https://cimg6.ibsrv.net/gimg/www.cor...3d351f040e.jpg
7416 LS6 crank

the Mercruiser 365 Magnum is a 1971 Chevelle LS-6 with a crappy .480 lift no duration no overlap marine cam. so there are more cranks-rods-blocks-rectangle heads out there than many realize.

Didnt catch what cam are you runing, final CR and intake?
Headers I assume? Keep the info coming, love build threads

Yes Headers, 10.5 CR, Sig Erson Custom Solid Lifter Camshaft 274/282 238/246 .585/.585 110 LC.
Estimates at this point vary from 530 to 550HP @ 5800.
Cam is very similar to an LS6 cam, but with mods: modern faster lobe ramps, way more lift, and 8 degree split duration between In/Ex. Overall .050 duration about like an LS6.
I still want a decent enough idle for vac and my wife, and cruising around, but it should really rev when I hit it. That won't ever happen with her in the car :nono:

Sq port heads, anything being done with them? Would personally be temped to mill the logo of a nice aftermarket ones off and paint it orange just for the power increase! Ought to have real good manners, fun build.

stick or automatic? didn't see it mentioned, or I'm blind, what's new.

Orig LS5 car with 4 spd stick, stock M20 C.R. 2:20 trans. 3.36 rear gear. Found a very nice set of 074 snowflake aluminum rectangular port heads for it, sort of the keystone part of my LS6 clone build. Also a 4803 LS6 Holley. The heads look they have some nice port matching work on them but nothing too radical. Might be a little better than stock ones not much. I intend to have them flowed and the engine dyno'd, just for fun.

OK back to my schooling by Jeff.
There were a couple of items we didn't do to the engine that might be just as important as the ones we did.
I tend to do a lot of research and one of the tricks I wanted to apply to this motor was Total Seal gapless top rings. 1% blowby and 10-14HP sounded worth it even if the cost was a little high at $25 per HP. He just told me no, and I really had to bug him for a reason. Apparently he and his customers tried them a few times, and every installation had some kind of problem. On the race engines they could barely tell the hp difference, and the motor seemed to fall-off rather quickly. On the street motors with PCV systems there were tuning issues and oil consumption issues. In all instances, they switched back to standard rings and the issues went away. Well so much for that. At least I got to assemble the rings and pistons and contribute. I didn't even mind when he double-checked everything. I know of a friend who put his rings in upside down once and had to re-do the motor a week later to stop the smoke cloud!
https://cimg8.ibsrv.net/gimg/www.cor...1e4a6842d9.jpg
IIRC the top ring was a moly one to seat faster, and the 2nd ring was harder steel. It certainly was tougher on my fingertips.

After this lesson I also brought up the fact that perhaps the piston domes need to have rounded edges for better flow. I got schooled again. His normal race motors are 15.8:1 C.R since they are running on Methanol and have some very serious domes that require hand fitting. I had helped with that before. In mine he chose domes that were low enough (.24") that they didn't get close enough to the spark plug in the head to obstruct the flame front since the plug is above the dome. So no hand fitting required.
https://cimg6.ibsrv.net/gimg/www.cor...311acf70c4.jpg
You can see how much higher the spark plug is in the chamber vs the dome.

These pistons have a pretty high quench area and deep valve relief for larger then stock cams. For comparison here was a readily available GM piston with a very low dome in a 9.5:1 454. I think he said it sits pretty far down in the hole too, and the valve notches are too small for a high lift cam. I didn't look the GM number up but from the 9.5 CR alone, these sound like stock 71 factory LS6 pistons. Check out how different the domes are on these two pistons!
https://cimg9.ibsrv.net/gimg/www.cor...989e28441b.jpg
GM 9.5 CR piston with low dome.

One more thing about the rings. If you look at my ICON IC783 pistons two pictures up, by the head, you can see that the piston pin is so high due to the .25 longer rods, that the oil ring goes thru the piston pin area. There is no piston land for the oil ring near the pin! The solution was a 4 component oil ring instead of the normal 3 component.The extra steel ring becomes the lower lip for the rest of the oil ring parts. Then the rest of the oil ring goes in like normal.