YTread Logo
YTread Logo

665 Cubic Inch (10.9 Liters!) Monster Big Block Engine Build w/ Prestige Motorsports

665 Cubic Inch (10.9 Liters!) Monster Big Block Engine Build w/ Prestige Motorsports
when you want gobs of horsepower and torque at the touch of the throttle it's hard to beat

cubic

inch

es and this

engine

has it in spades today we're

build

ing a 665

cubic

inch

big

block

beast with our friends at

prestige

Motorsports

in Concord North Carolina we missed out on video in the short

block

assembly of this

engine

so I hope you'll excuse a few photos as we get started we don't normally do this but this

engine

is so unique we thought it would still be worth it the whole point of this

engine

is to create an astounding amount of power from a naturally aspirated pump gas

engine

and

prestige

decided to do it with tons of

cubic

inch

es this specific bill will be going into a high-performance airboat but the same recipe can make an unbelievable tire roaster in a car or a truck it all starts with an aluminum

block

from Braddock's the Chevy style big

block

s from Britax has a lot of great features namely it will take the 4

inch

600 thousands bore we'll be using it also has the cam tunnel raised four hundred thousand seven

inch

and a very tall eleven point one

inch

deck height to allow for a massive five

inch

stroke to handle all the power we'll be producing there are billet steel splayed bolt main caps and some seriously beefy webbing in the lifter Valley plus it's all aluminum so even though the tall deck

block

means this

engine

will be both taller and wider than a standard big-

block

it will still be lighter than a smaller iron

block

after...
665 cubic inch 10 9 liters monster big block engine build w prestige motorsports
machining and blueprinting the cast aluminum

block

one of the first modifications

Prestige

made was to install piston doors quarters that pump pressurized oil to the underside of each piston this helps keep them cool even during extended full-throttle blasts of course you can't make the most of nearly 700

cubic

inch

es if you can't move enough air and fuel into the combustion chambers to keep all those

cubic

inch

es properly fed that requires a pretty impressive set of cylinder heads and for that task

prestige

chose air fuel researchers new 18-degree Magnum cylinder heads because they are about the only option that can keep up with the demands of this

engine

AFR's Magnum straighten the valves up to an 18 degree angle versus a conventional 24 and they paired that with intake ports that have been raised a full of an

inch

combine that with two

inch

400 thousands diameter intake valves and you get ports that can flow almost 500 CFM that makes this a FRS highest flowing big-

block

cylinder in the chambers and both intake and exhaust ports are CNC cut and the combustion chambers are sized at 90 CCS you will notice a spacer bolted to the intake side of the cylinder head in these photos and we'll get more into that later

prestige

has had the intake and exhaust flanges CNC cut to accept O rings to eliminate the need for gaskets this isn't currently a standard option for the AFR heads but it's something

prestige

did themselves now let's get started on the

build

...
665 cubic inch 10 9 liters monster big block engine build w prestige motorsports
the crankshaft is going to have to withstand bucket loads of torque applied through the combustion of lots of air and fuel so a Kali's Magnum series crankshaft was chosen and clamped into place with displayed bolt billet main caps the rest of the rotating assembly is made up of a set of Oliver billet I beam connecting rods and custom Pistons from je the connecting rods are 7

inch

es Center to Center and that's 865,000 longer than stock the je Pistons are custom slugs with a significant dish to help keep the compression ratio down but after running the numbers and realizing just how much air the fr cylinder heads can float

prestige

decided to go with an even more aggressive cam design from Comp Cams than they had originally expect out to make it all work they needed to hand cut the valve pockets just a little bit deeper here if you look closely you can see the larger valve pocket cut into the piston on the left-hand side and now that catches us up to where I actually got involved in the bill here lead

engine

assembler Larry broker installs ARP head studs into the

block

head studs aren't as popular in street machines where he can make the cylinder heads difficult to remove with the

engine

still in the car but that isn't an issue on a wide open airboat and studs are better at maintaining good cylinder sealing without distorting the cylinder bores and here's a better look at the Pistons and the bores the dish you see is 233 thousandths of an

inch

deep with...
665 cubic inch 10 9 liters monster big block engine build w prestige motorsports
the volume of 44 CCS along with the 90 CC combustion chambers that keeps a compression down to a pump gas friendly ten point four to one the bigger valve reliefs that were cut in the top of the Pistons are because of the very aggressive solid roller cam from Comp Cams at 50,000 Slithe this cam is ground with 274 degrees of duration for the intakes and 282 for the exhausts with a hundred ten degrees of separation Grouse valve lift with 1.7 ratio rockers is 717 thousands for the intakes and 715 for the exhausts up front there is no conventional timing chain instead

prestige

is using a belt drive setup from Jessel belts do a better job of providing consistent valve timing and they're more resistant to stretch in this shot you can see the crank trigger installed and one of the magnets lined up with the trigger check out these custom made spacers at the front and rear of the

block

these must be bolted in place before the heads and spacers can go on hang in there you'll see exactly why in a minute with AARP head studs in broker is ready to lower the F our cylinder heads in place notice the intake spacers which are approximately an

inch

thick are already bolted tight to the intake side of the heads the spacers are necessary because there is currently no cast intake manifold available for an eleven point one

inch

deck

block

a fabricated intake would be an easier option but it turns out in an airboat application the vibrations over an extended amount of time can cause a...
sheet metal in taking the crack so

Prestige

had to figure out a way to make a cast intake for a ten point two deck

block

work the raised intake port makes very practically straight shot to the top of the valve even with the spacer in place Broker torch down the heads 270 pound feet in three steps with arp ultra-torque lube on the threads and here's a better shot of the China wall spacers with the heads on you can see how they are necessary to seal off the gap because the spacers create extra length on the intake side of the heads the valve springs are a double nested set up from AFR held in place by titanium retainers the springs are rated at 240 pounds per

inch

and at full lift that comes out to 650 pounds of pressure now we're ready to move on to the valve train the bro Dix

block

is designed to work with tie bar lifters and that's exactly what we're doing here with a set of these solid rollers from BAM tnd was sourced to provide the rocker arms this is a shaft mount rocker system and broker installs the rocker stands to the cylinder head each stand is secured to the cylinder head with 12 fasteners helping create a very stable valve train the 7/16

inch

bolts are torqued to sixty pounds each the pushrods are heavy-duty units that and flex even with high spring pressures and extra length required from the tall deck height these 7/16

inch

diameter push rods are made by men with a 120,000 s wall thickness the intakes are 10

inch

es long while the exhausts are...
longer at 10

inch

es 700,000 and with the push rods in place the rocker arms can finally go on each rocker pivots on its own shaft with two fasteners securing it to the rocker stand these are aluminum rockers from t and d and the stock ratio of one point seven to one broker gives each a cold lash of four thousands with the aluminum

block

and cylinder heads that should open up to a hot lash of 20 2004 the intakes and 24 for the exhaust to help free up a little extra horsepower broker installs a belt-driven vacuum pump from Moroso that's the puke tank and breather for it on the right and here's a look at a FRS valve covers and single plane intake both designed for these 18 degree heads the Magnum intake fits the heads perfectly on a standard neck

block

but it needed to be modified to work with this specific package and you can see the changes we've made on the underside in this shot the box in the front is an all bifel that was going to be used for the vacuum pump but it turned out that the pump pulled too much oil from this position so the vacuum ports were moved to the valve covers the big change is at the back the customer wanted to run a distributor and not individual core packs so

prestige

had to modify the distributor mounting boss because the intake is now sitting too high with the spacers they did this by cutting out the distributor mounting boss from the deck of the intake lowering it and then welding it back into position remember this is a lot tougher...
than it looks because the distributor mounting boss location must not only be correct vertically but also laterally as well as forward and aft in order to ensure correct gear alignment between the distributor gear and the camshaft if it's not right you're going to be tearing stuff up here's the final result and although the process was quite time-consuming everything turned out great and with that we're finally able to get this ten point nine liter behemoth on the dyno the carburetor is a holley gen3 ultra Dominator this is a race specific card with three circuits and it's rated at fourteen hundred and seventy-five CFM it takes a big carb to feed big

cubic

inch

es and that's exactly what we've got here plus the Holley sitting on top of a one

inch

four hole spacer we started off using a set of prestigious Dino headers to baseline the

engine

these headers have a single two and a quarter

inch

pipe feeding a four into one merge collector to break in and a little bit of tuning our biggest bruiser did incredibly well especially when it comes to producing ground-pounding torque because this

engine

has an extremely long 5-

inch

stroke

prestige

didn't want to push the RPMs too high as an airboat

engine

the maximum rpm will be somewhere in the mid 5,000 rpm range but it will have to be able to run there for hours we started off the pull at 3500 rpm and it was already making 730 pound-feet of torque at that point and it just rose from their peak torque was...
910 point 7 at 5,000 rpm and by the time we pulled back on the handle at 6200 rpm it was still making 834 peak horsepower was 984 point 5 at 6200 rpm and still climbing after that we made a swap to a set of custom headers

prestige

built especially for this

engine

besides having a shape more suited to airboats these headers are a little larger with two and a quarter

inch

primaries and step ups two two and three eighths of an

inch

in the secondary tubes like the Dino headers the pipes merge into four into one collectors it turns out our 665 was able to make use of the larger headers the custom headers made significantly more power all the way through the curve up until 5700 rpm peak torque jumped nearly sixteen and a half to nine hundred twenty seven point one and at 3500 rpm it was an incredible 50 pound-feet better horsepower was also much improved all the way up in the range until the dyno headers finally caught up at 5700 rpm peak power for the new headers was down by little over 22 the 960 1.6 at 6200 after that we made one final test

prestige

wanted to see if more header length would help power production so 12

inch

sexes of pipe were added to just above the merger yourself this time around weren't nearly as concrete throughout the curve the torque and horsepower lines of the headers with the extensions nearly overlaid the curve of the original headers the peak torque was still better with the original headers 927 point one two nine twenty one point six so we're...
sticking with the headers without the extensions overall this big

inch

big

block

is an absolute beast no matter if it's in a boat or a shovel 960 horsepower on pump gas is awesome enough but when you can go from 3500 rpm all the way to 6200 and never drop below 780 pound-feet of torque you are talking about an absolute

monster

that can turn a tire rubber into the gray smoke of fun eight days a week hey thanks for watching