There’s something intoxicating about cheap speed. In the previous installment of this engine build, we got our hands on an extremely budget friendly Chevrolet Performance 195-horsepower crate engine and subjected it to a healthy dose of boost from a Weiand 142 Pro Street supercharger. Not only did the little-engine-that-could respond quite favorably to unnatural aspiration, it excelled with the extra atmosphere being stuffed down its bores. A COMP Cams blower cam (PN K12-556-4) further upped the ante, bringing our total engine output to a respectable 409 horsepower and 435 lb-ft of torque – all for a bottom line of only $3,979.91.
Always on the hunt for more power, we put ourselves in the shoes of an average hot rodder and decided the next best, and most logical, upgrade for the engine would be a budget set of cylinder heads. We could have saved a couple of bucks by sticking with cast iron; but, being that the small-block Chevy has one of the greatest aftermarket parts caches of any engine platform, we turned to Brodix for a set of their IK200 cast-aluminum cylinder heads.
The IK200 is one of the best-kept secrets on the cylinder head market and fit the budget theme of our build perfectly. The “IK” moniker, short for Iron Killer, is a nod to the price point of the head lineup, which cost $809.36 a pair — or $404.68 each — (bare) or $1,329.97 assembled, directly from Brodix. We ordered up an assembled pair of heads with 70cc chambers to swap onto our Blown Budget project.
It is important to note that if you decide to order the heads bare, you will need a set of intake and exhaust valves, valvespring locators — also known as spring cups, which are necessary in any aluminum head application to keep the hard steel valvesprings from chewing into the soft aluminum — valve stem seals, guideplates, rocker studs, and the necessary shims to set your valvesprings up to the proper installed heights. While you might be able to save a little coin if you have some of those components already, ordering the heads as a complete package takes a lot of the headache out of a swap.
With our new heads in tow, we lugged the blown small-block back to Westech where it was again strapped to the engine dyno for some inquisitive flogging. We pulled the low-performance cast-iron heads — the set that ships with all 195-horse crate engines — off the block and installed our IK200s. A fresh set of Fel-Pro Performance MLS head gaskets was used to seal in the fire and the flames.
After bolting the heads onto the engine, we installed our COMP pushrod guideplates and a set of ARP rocker arm studs. We also took this opportunity to add a set of COMP roller rockers with a 1.6:1 ratio to add a little more lift to our cam.
We bolted the blower manifold and blower back on the engine, making sure to torque it to Weiand’s specs, and sealed it up with the original Chevrolet valve covers. Next, Westech’s Steve Brulé set the timing and readied the engine to make a few more power pulls. Our hearty mill fired up on the first pop and it didn’t take long to realize the addition of the new heads was a wise and fruitful decision.
The engine responded extremely favorably, with power and torque up across the board (see dyno graph). In fact, torque output didn’t fall below 400 lb-ft until the very top of the pull, 6,000 rpm. That’s a lot of grunt!
Speaking of power, the new lungs brought it up to 451 horsepower at 5,900 rpm. That is a solid 42-horsepower increase over our last dyno – the cylinder heads being the only change. The heads allowed the engine to carry power higher in the powerband before dropping off, but did not sacrifice any mid-range performance. The better breathing ports and bigger valves bolstered performance everywhere. The 70cc chambers also bumped the compression of the engine up slightly from the 76cc units the 195-horse crate engine is assembled with.
We actually found the stated compression of the engine (8.5:1) to be lower than advertised. With a large piston down-bore and around 17cc dishes in the piston, the original compression of the engine was more like 7.8:1 than the claimed 8.5:1. Installing the new heads brought it up to about 8.2:1.
Through our testing, one unusual trait arose in our small-block’s demeanor. Typically, on a smaller-displacement engine, such as this one, a large runner (200cc or bigger) can make the powerband lazy toward the bottom of the rev range. Our theory is that because we had a blower force-feeding the cylinders, we opted for the 200cc variant of the IK series, and per these results, we are glad we did. Also, the freer flowing heads did contribute to a boost drop as more air found its way into the combustion chamber. Peak boost in our last test with a stock long-block and COMP Cams blower cam saw boost top out at 9 psi, whereas in this test we saw only 7.5 psi.
We have a few more budget upgrades we’d like to try out on Blown Budget before we find a home for the engine. As of now the engine has around 35-40 dyno pulls on the stock Chevrolet Performance 195-horse crate short-block and we have yet to experience any problems. We’ll keep flogging it, but now that we’ve cracked the 450-horsepower barrier, 500 is starting to seem well within reach. Stay tuned as there are plenty of bad ideas to come.
|Budget Breathers – Brodix IK200 heads (2.02/1.60 valves)|
|Lift (in inches)||Intake cfm||Exhaust cfm|
With peak flow numbers of 261 cfm intake and 176 cfm exhaust, the IK200 heads represent a huge performance bargain for their price to flow ratio. They are also available in 180cc runner sizes (IK180) and in a fully CNC ported 210cc (IK210) variation as well.
1. We again strapped our 195-horse crate engine, supplemented by a Weiand 142 Pro Street blower, to the dyno at Westech Performance for another round in the ring.
2. The old 76cc chamber, low-performance iron castings were yanked in favor of a new set of lungs from Brodix.
3. Here you can see the stock cast pistons of the Chevrolet Performance 195-horse crate engine. Note the tapered edges and huge dishes with four valve reliefs.
4. To seal the combustion chambers, we used a set of Fel-Pro PermaTorque MLS head gaskets.
5. Westech’s Steve Brulé muscles our new set of Brodix IK200 cylinder heads onto the engine.
6. The new heads look right at home on the small-block and we couldn’t wait to see what kind of power they would bring to the table. Fel-Pro Performance intake gaskets were used to seal the blower intake to the heads.
7. A set of COMP Cams Pro Magnum roller rockers, in a 1.6:1 ratio, were used to bump the conservative lift of our cam (0.462/0.480) up slightly. A Fel-Pro Performance reusable valve cover gasket seals the head.
8. In the spirit of thrift, we retained our Goodwrench valve covers. We kind of like them, as they give a nod toward the foundation this powerplant is based on.
9. If you decide to order the heads bare, you will need a set of valvespring locators, and enough shims to get your springs set to the proper installed height.
10. Here is a close-up of the 70cc chambers of the Brodix IK200 heads. They feature a 2.02/1.60-inch valve package and hand-blended bowls. The heads can be milled to reduce the chamber size, or ordered in a 64cc size.
11. The numbers don’t lie. Here are the dyno results from our second test of Blown Budget. Look at that torque! Only at the very top of the pull does it dip below 400 lb-ft. This mill would make such a fun street engine with ample grunt to pin your buns in the seat.
12. Here is a comparison chart of Blown Budget in all of the different configurations we’ve tested. Look at the vast difference in power output between the stock (blue) and our latest dyno (black).