Ready-to-run 8 Stack Engines

BASIC ENGINE or READY-TO-RUN?

The internet offers countless choices for buying an engine and you have to do your research.  The engine is the second largest purchase you’ll make after buying your car, so you need to get it right the first time.  Whether you order an engine from us or not, this page will give you the basic guidelines to keep in mind when building an 8-stack engine.

The first thing you must decide is whether you want a complete or incomplete engine.  One choice is an incomplete “long-block”.  This is a basic engine package that you’ll finish assembling yourself and get running on your own.  At the other end of the spectrum is having a complete engine built to order with your 8-stack system already on it and shipped to you turnkey.   This is the type of engine service we offer.  We run every engine, tune it, and ship it “turnkey”.  Dyno tuning is optional.  All our engine orders start with an order for an 8-stack system. If you need an engine to put it on, we can provide the total package.

Smallblock Ford 363 stroker for an FIA 289 Cobra.

If you’ve already spent some time shopping for an engine, then you’ve learned that most new engines are sold as a “long-block”.  This is a basic engine assembly consisting of the block and heads with an intake manifold, maybe a carburetor, and a distributor.  They come with a pre-selected camshaft that can’t be changed at the time of sale because they’re pre-built engines using a standard bill of materials.  Long-blocks come with all the major parts, but they are incomplete.

A long-block typically includes a single four-barrel intake manifold that you will remove and sell on eBay, and it may or may not have a distributor that is usually too large in diameter for 8-stack clearance, so most likely, it will also need to be changed.  You will usually need to buy a water pump, starter, pulleys, and any other bolt-ons that are not included.

It’s up to you to buy those other parts and install them, or pay someone else to do it. You might also need to change the cam and ignition for compatibility with an 8-stack induction system.  

8-STACK ENGINES vs. 4-BARREL ENGINES 

An 8-stack engine isn’t complicated; it’s just a little different than a four-barrel engine.  An engine is basically an air pump and its efficiency depends on the compatibility of its components.  When everything works well together, the engine will be efficient and deliver a balanced combination of power and drivability in the workable rpm range it was designed for.  But with incorrectly matched components, an engine can be an incompatible collection of parts that don't get along well together.

The main thing that differentiates these engines is that they use “independent runner” manifolds that don’t have a central distribution plenum under the carburetor(s). With an I.R. manifold, there are eight separate, isolated columns of air, one for each cylinder.  There is no inter-communication between the eight incoming air columns or the eight cylinders.

This is why I.R./8-stack engines are known for having instant throttle response.  When you crack the throttle, you’re moving eight small columns of air, not one big mass of air in a 4-barrel manifold plenum. The smaller the air mass, the faster it moves.  The faster it moves, the more torque and power the engine makes.

The biggest enemy of the 8-stack engine is what’s called “reversion”.  This happens when the incoming air columns are disturbed by reverse-flowing pulse waves sent back into the intake manifold from the cylinders because the valves are opening and closing at the wrong time in relation to piston movement.  This is the result of using an incorrect cam in an engine with an independent runner (non-plenum) manifold.  This disturbance to the incoming airflow results in lost horsepower. 

The camshaft coordinates the valve opening and closing events in relation to the piston position in each cylinder.   As the pistons move up and down, the valves open and close, and the timing of these events has to be optimum.  If these events are only a few degrees off, it can make a huge difference. This is why the camshaft is the heart of the engine.

At high rpm’s on a dyno, reversion looks like a thick fuel mist coming out of the velocity stacks. When the reversion is this severe, it’s called “standoff”, and this is what happens when an I.R./8-stack manifold is mounted on an engine that has a cam with excessive valve overlap.

On a 4-barrel engine, the reverse pulses still occur, but they never get as far as the carburetor.  This is because when the pulses get up into the open plenum area under the carburetor, they’re drawn into whichever cylinder is on the intake stroke. 

4-barrel engines aren’t as fussy about valve overlap.  The Lobe Separation Angle (LSA) of the cam governs this.  We only use cams designed for use with independent runner inductions. 

Smallblock Chevy engine with Weber crossram, ready for the dyno. This customer specified his own color and ordered the induction unit to match. A typical custom engine package.

COMPRESSION RATIO

Another important consideration for any 8-stack engine is the compression ratio.  This is extremely important for throttle response.  We use the ideal compression ratio of 10.5:1, and our engines run on 91-octane pump gas.  If you want a higher compression ratio, just let us know. The only substitute for a minimum 10.5:1 compression ratio is a lot of cubic inches, which will offset a lower compression ratio to some degree. 

OUR ENGINE PACKAGE

Over the last four decades, I’ve probably tuned more 8-stack engines than most people who are still left on this planet, whether in customers’ cars or on the dyno.  My own experience, combined with the engine building expertise of Darryl Fitzgerald, my engine builder, led us to offer complete, ready to run 8-stack engines. 

Our engines reflect everything Darryl and I have learned working together on the dyno and street testing.  Eight stack engines are what we know and this is our specialty.

Your engine will come with everything, including a small diameter MSD Pro Billet distributor, ignition wires, hi-torque starter, aluminum water pump, pulleys, fuel pump, and either an Aviad or Canton oil pan depending on your application.

When you call, I’ll discuss your engine needs with you.  We will discuss all details, including what valve covers you want, the pulleys and belt drive type, and any other special details that should be noted.  Every engine is built to order.  This is a personalized service and I will work one-on-one with you. 

You will select the valve covers you want on your engine. Competition 289 Cobra valve cover is shown.

Engines can be ordered with any type of front drive. Shown here is a custom billet aluminum drive with polished alternator and A/C compressor.

I will coordinate your engine order with Darryl, and once it’s in place, you’ll then work directly with him on the engine build and its progress.  When your induction unit is finished, I ship it to the engine shop to be mounted to your engine.

When your engine assembly is complete, it is started-up and run on the test stand.  This eliminates any anxieties you might have about starting a new engine for the first time on your own.

Once it’s running, the cam is broken-in and any leaks or other startup gremlins are resolved, should they pop up. The valves are adjusted, the carburetors (or throttle bodies) are synchronized, and after one complete heat cycle, the cylinder heads are re-torqued.  The engine is then started and run a second time for its final check. 

If you want your engine dyno-tuned before shipment, this last step is optional. If we run it on the dyno, your engine will be put through its paces, redlined several times, and proven. You’ll get the dyno sheet.

When you install it and turn the key for the first time, there will be no surprises. It will start as if you parked it yesterday.  As the saying goes, you get what you pay for.   

We ship our engines everywhere in the world and we welcome orders from customers and specialty shops anywhere.  We ship about one-third of our engines to locations overseas.

Shown above is an engine for a Daytona Coupe with 1" shortened stacks and a turkey pan. We no longer sell turkey pans since our fabricator passed away, but if you buy one from Nick Acton, (www.actoncobra.com) we'll fit it and install it. These pans have to be pre-fitted before the carburetors are mounted and it's a tedious process to trim it for linkage clearance. If you need one of these installed, we'll do it and ship the engine assembled as you see here. Fitting and installing one of these pans is not recommended for the average hobbyist.

ENGINE OFFERINGS

We specialize in Ford engines for Cobras and GT40’s, but we build them for hot rods, Pro Touring cars, and every other conceivable application. 

Typically, our smallblock Ford 302-based 331/347/363 strokers range from 430 to 470 hp and our 351W/ 427 strokers produce power in the 550 hp range.  We also build 351C engines which are available as 408 strokers.

Our Chevrolet engines include smallblock 350’s, 377’s, 383’s and 427 strokers.  The bigblocks range from 454’s to a 502 strokers.

Our engine shop is a small specialized facility that one of our customers labeled as a “boutique” engine shop, and I suppose it is.  Our standard lead-time for an engine is 8-10 weeks, but it can get backlogged at certain times of the year.  This depends on parts availability from vendors, and the general workload.  Please allow enough lead-time.  It’s always best to assume it may take longer.

Tony Lewis

Jim,

Finished the Unique Motorcar replica of CSX 2001 this week. I appreciate all of your help with the Webers. All of your calculations and parts were dead on as usual. The power out of the 302/ 362 Dart block and heads topped off with the Webers is crazy. The little guy is turning out almost 600 HP and sounds awesome. 

Thank you again.

Tony Lewis

Gjon Vataj

Hello Jim, Just wanted to thank you on all your help with the Cobra I had here. You my friend are a gentlemen and a scholar.  Ended up working out fabulous. It made on our Mustang dyno 332whp and 343wtq. Its a small animal! Here are a few pics. She's beautiful! 

Gjon Vataj, CT

Wayne

Aloha Jim,

Received the carbs with linkage today and the linkage looks SWEET !  Very nice job putting it together, it’s solid and with the adjustments available I should have no problem getting it to clear any obstacles…thanks for the clean looking linkage and I can’t wait to hook it up this weekend.  

Mahalo,

Wayne

Anthony

Jim,  

The set up looks great, your linkage/brackets are well worth it. Turn around time couldn’t be better.  Dealing with you was nothing but informative, personal, and professional!! I will let you know how it runs, gonna take 30-60 days for me to get the car back together.  

Thank you!

Anthony

Cameron Parsons

Your package arrived today.  Thank you.   

I warmed up the car, swapped the Idle jet holders.  Resynched the carbs (didn’t really need it, but wanted to be as perfect as possible), reset the idle screws (which took quite a bit to get just right, adjust and just again, double checking everything) and took it for a test drive.

WOW.  Smooth as silk, no hesitation, not ‘bobble’, just smooth responsive power.  I can’t tell you how it has transformed the way the car drives.  Instead of me being hyper focused on throttle control to minimize poor behavior, it just purrs.    I even tried to get it to misbehave, low revs high gears low speed, perfect.  Pulls smooth from idle, no issues. I haven’t opened it up yet to really try out the transition, but feel confident it will be fine. 

Thanks for the support.  Can’t believe the difference.  Just Wow.

Cameron Parsons       

Tim Mackey

Test ride 2:

HOLY SHIT BATMAN !!!!

Pulls harder from low RPM's than ever.

No Studder

Makes more power over full range of RPM's than ever did before - SCARY AT FULL THROTTLE

Evening out all the carbs exactly @ 7/8 it now runs very smooth, with no ratty tendencies

Feeling the exhaust output with my hands I notice it's cooler than before jet changes and very even on both sides

Temp gauge runs about 10 degrees cooler now too @ cruise (180 vs 190)

Smells a bit rich in garage but hey, this is a hot motor with a big cam and heads. 

Thanks so much Jim!  You are THE MAN!!!!

Best Regards,

Tim Mackey