Shortblocks, Longblocks, and Crate Engines

There are 4 common ways to purchase or build an engine. You can build an engine from scratch....You can purchase a completed crate engine....You can also start somewhere in the middle with a short block or a long block. I wanted to add this article to the site with some explanations and links for current and future cobra and hot rod builders.

Crate engines have become the hot ticket in the last few years. Anyone can now purchase a high quality, complete engine, for as little as $3000 and up to $42,500 for crazy Sonny Leonard Chevy monster mill. Most Ford 351w crate engines run from $5000 - $10,000. More and more stroker combinations are available for both small block and big block. Here are some of the more common 351 combo's available as crates

ci. bore stroke
351 4.00 3.50
357 4.03 3.50
377 4.03 3.70
383 4.03 3.75
393 4.03 3.85
408 4.03 4.00
418 4.03 4.10
427 4.03 4.17

Here are some of the various engine builders who sell Ford crates.

http://www.coasthigh.com
http://www.houseofcobras.com/engineshop.htm
http://www.bennettracing.com/
http://www.enginefactory.com/351W.htm
http://www.ford-power.com/
http://www.golensengineservice.com/
http://www.indymustang.stangnet.com/custom.html
http://www.jcperformance.com/
http://www.panhandleperformance.com/
http://www.speedomotive.com/
http://www.dndmotorsports.com/general/main.asp
http://www.fordracing.com/

After crate engines, next come long blocks. These engines are approximately 75% complete. Here is a picture of a DSS long block. Most long blocks require the following items to complete the engine. They are missing the following bolt on items:

timing cover
water pump
intake manifold
carburetor
belts and pulleys

Most of the sites listed above also sell both short and long block kits.

Short blocks require a little more work to finish. Short blocks are generally the completed block with the rotating assembly installed. This includes

block
crank shaft
pistons
rods
bearings

Here is a picture of a DSS short block. Essentially the dirty work like machining and clearancing has already been completed.

This is like building a scratch cake. You start with the bare block. You then have it machined to the proper specs and clearances. You then add the rotating assembly and other parts. In the old days, this was how all engines were built. Now with the performance market exploding, short blocks, long blocks, and crates are becoming very popular to save time and money. Here is just a block.

A stroker kit is a brand new rotating assembly to use with your existing engine block. Stroker kits change the cubic inch displacement of an engine by increasing the crank stroke and the distance the piston travels. Stroker kits are these 3 items: crank, rod, pistons, along with bearings and rings. Here are some great pictures of Scat stroker kits.

Here are some sites for stroker kits

Coast High Performance
Speedomotive
DSS
PAW
Flatlander
StrokerKits
Custom Design

In my opinion, the two biggest engine components contributing to final HP and TQ, are the cylinder heads and the camshaft. If you want to find power, these are two great places to start. Money spent on good heads and a good cam, is money well spent. My three favorite heads for small block fords are:

Edelbrock Victor Jr
Trickflow Twisted Wedge
AFR 185

These heads will get almost any 351 into the 400-500 range. There are bigger heads available, but pay attention to their header exhaust area and bolt patterns. Victor, Trickflow R, and AFR 205s etc, all use non stock header bolt patterns and will require some thought and research into finding headers that bolt up and also fit the engine bay of your car.

When selecting a cam, I think it is always a good idea to call the cam manufacturer and double check with tech support. Does the cam meet your needs and is it the proper cam for your compression ratio. After heads and cam, compression ratio is one of the next most important factors in determining an engine's output. Today's pump gas can generally run in an engine of up to 10.5:1 compression. Cams generally match a compression ratio. If you over cam, you will be causing yourself grief and frustration down the line and may even lose your engine due to detonation. Here are my personal favorite cam grinds for 10.5:1 compression engine cobras. These are on the aggressive side so they are not for everyone. These are high HP grinds at the cost of TQ.

CRANE
448601 246 254 .579 .598 108 112
448511 254 262 .599 .599 105 115
448031 244 252 .619 .640 105 115
449761 232 244 .563 .595 107 117
449561 232 240 .563 .584 107 117
449571 244 256 .595 .595 107 117
449581 244 256 .595 .595 105 115
449811 236 244 .574 .594 109 119

COMP
35-522-8 232 240 .565 .574 112
35-773-8 254 260 .621 .627 110
35-772-8 248 254 .614 .621 110
31-641-5 265 276 .600 .593 106
31-609-5 250 260 .568 .592 106
31-332-5 260 260 .565 .565 110

LUNATI
51018LUN 242 252 .560 .576 110 106
51019LUN 248 256 .602 .602 108 104
51021LUN 248 258 .593 .624 108 104

TRICKFLOW
TFS-51402002 236 248 .574 .594 110 105

ISKY
371284/294 284 294 .544 .573 110

CROWER
15445 254 260 .597 .547 110

I am building engine #3 from scratch and it is going along fairly well. I just got word from Jody the engine machinist that my block and crank are done. My crank was turned 10 under but that did not clean it up do to the damage level and so they went to 20 under. I called out the main bearing and rod bearing clearances and Jody worked backwards from that. For those of you who have built engines from scratch, here are the specs I am shooting for

Main Bearings...0025" - .0030" | .0030 desired
Rod Bearings....0020" - .0025" | .0025 desired
Piston to Wall .0050" - .0065"
Crank Straight..0010" - .0015"
Rod Side........0010" - .0020" | .0020 desired
Crank Endplay...0040" - .0080"
Cam Endplay.....0010" - .0070"

One of my piston skirts was slightly deformed and one rod was really burnt and so I am ordering replacements from Probe industries and taking them down to Jody next week.

Brian at TEA has been working on my heads. I fedexed him my new springs since they prefer to port the heads and completely set them up with proper shims and spring loads. I am expecting the heads back in 2-3 weeks. I have about 100 little parts on order at racesearch to various manufacturers and those are all slowly dribbling in. Here are picks from the engine tear down. You can see that the bearings had little material left on them. I was surprised the engine ever ran.

I was a little sad that my cam was toast. The gears had been worm down like the distributor gear. I placed the order with Crane. They said this is a model that they custom grind and they were out of the raw stock so it would be end of July.

Of course I have to order some exciting tools to build the engine and check all clearances =) I decided to have Armando build me a custom GT40 oil pan which is 1.75" shorter than my canton. It was just a matter of time until I whacked the other pan on a speed bump. I am also pushing the envelope as I go into the realm of the Super Victor in a search for HP.

P.S. THE MONSTER STROKER
Dino Boothe and I love to bench race and daydream about monster stroker kits like the 454 from flatlander. You can only get over 427 with certain race blocks that allow a giant overbore. Well today Adam wrote me a great email. He discovered a new SCAT Pro-line crank for the 351w that will be a HUGE 4.5"
look at Ford 4340 near the bottom

Adam wrote that this combined with the 4.155" bore Siamese block would net a 488.13 cubic inch motor! I almost fainted. Then I decided to take it one step further. Take the new Scat 4.5" crank and pry it into the new Dart 351w block, over bored to 4.185. Oh My Word. That's a
495.20 ci small block! Try the math right here. Just wait until I tell Dino.