it was finally showtime for bruiser! we’ve shown you all the planning and detail work that goes into a serious pump gas street motor. building race engines is one thing, but building street engines brings a whole different set of requirements and compromises that need to be dealt with.

Once all the mock-ups and measuring were completed, it was finally time to assemble the engine one last time. During this phase, one must still look closely at every part and make sure it’s perfect. Knowing we were going to thrash this engine for all its worth on the dyno, it had to be build right to survive.

final assembly:

Since dyno time equals money, it’s always best to make sure your engine is ready to run immediately and make pulls when you arrive. I set up the first version to run with the flat-tappet cam. This allowed it to run on my home test stand for cam break-in with only the outer valvesprings installed to make sure all went well. Bruiser made it through cam break-in just fine, so I reinstalled the inner valvesprings, re-torqued the heads and all other accessible bolts such as those on the intake and the oil pan.

Our dyno facility was none other than The School of Automotive Machinists in Houston, Texas. SAM is owned and operated by Judson and Linda Massingill, who turn out some of the most skilled engine machinists / builders in the industry. Their graduates are working on many of the big-name NASCAR and drag racing teams that you follow every week, as well as others that are working at many manufacturer and race shops around the country. They’ve always been great to work with and with their success at building winning race engines and cars, there was no doubt Bruiser would be under close scrutiny and would have to deliver the goods to hold his head up when we were done!

Putting an engine on the lie detector, otherwise known as the SAM SuperFlow 902 Dyno, can be awfully exciting, or terribly heartbreaking. But using SAM would also eliminate any worries about exaggerated dyno claims. I’ve yet to test a motor there that didn’t back up its numbers when we got it dialed in at the track. We experienced incredibly nice weather (for Houston) during our testing and found that the correction factors for the dyno were actually taking the numbers DOWN! The raw numbers in the mornings were actually higher than you see here and only off by one to two percent maximum during the late afternoon pulls.

When the big day finally came, we were met by SAM Instructor Chris Bennett. We unloaded the 555-inch beast, and in no time, we had it hooked to the dyno by the SAM crew and were getting warmed up. Chris and I reviewed the plans for testing one more time and verified that we had everything ready to perform all the cam / valvespring / pushrod / intake and carburetor changes we had planned. Had we only been planning on maximizing ONE overall combo, we would have spent all of our time running valve “lash loops,” changing cam timing, swapping rocker ratios, trying stacks of spacers, different headers, collectors, etc. Our plan was different. For these tests, we wanted to get some strong baseline tunes with respect to carburetor jetting and timing and then make some relatively dramatic changes in the engine configuration to give you an idea of what to expect. We would be testing the following configurations:

• Solid flat-tappet cam with multiple intake and carburetor swaps.
• A hydraulic roller cam with both hydraulic and solid-roller lifters installed.
• A solid-roller cam with various intake and carburetor tests.

For consistency, all tests throughout the two days were run with an open 1-inch spacer installed. All tests were run with 2¼-inch headers designed for a C1 big-block swap. All pulls were made on 93 octane pump gas. What you will see here was designed to give you some strong, no-hype information on “what does what” and “what you can expect.”

let the testing begin:

First up to bat was the solid flat-tappet combo with the Edelbrock Victor Jr. intake that was fully ported and modified by Wilson Manifolds to fit under a C3 L-88 type hood. I was secretly pulling for this combo to do well. I figured if we broke 700hp with a flat tappet, we’d be able to hold our heads up. I was really dreaming of a 750hp number, but most people thought I was crazy. We started the day with 31 degrees of timing and the 850 Demon carburetor that came with Bruiser on its old 496ci motor. The carb was very responsive and on its very first pull, it laid down 670 lbs-ft at 5,000 rpm and 713hp at 6,000 rpm … and was still climbing! We pulled the plugs, double-checked the dyno data, and determined the A/F mixture was dead on.

There is a lot of confusion mixed into advertising sometimes, but just like head flow numbers, there is a LOT more to how a carburetor performs than its CFM rating. There are many combinations of venturi size, shape, throttle bore size and booster design that all come into play. The 850 Demon and the Holley HP 1000 have essentially the same throttle bore size (1.750-inch) and venturi size (1.562-inch Demon/1.561-inch Holley), so they should flow and perform similarly, right? I personally think the HP 1000 Holley is still one of the best out-of-the-box carbs, so I was excited to get a chance to test it back-to-back against the Demon, which is also very well respected.

We did nothing but bolt the Holley HP 1000 on and made the next pull. That Holley HP immediately started posting bigger numbers and picked up 8 lbs-ft at the same 5,000 rpm, but look what happened as the rpm climbed … 29 more horsepower at 6,000 rpm! We were making 742.9hp already! When we checked the plugs, things looked a little lean. So we bumped the jets two sizes on the primary to 86s, and we upped three numbers on the secondary to 87s. We left the timing alone and decided it was time to spin it up a little to 6,500 rpm. The added fuel got us 685 lbs-ft at 5,000 rpm, and at 755.7hp, we found the peak horsepower to be 6,300 rpm. We next tried a few pulls with more jetting and timing at 32 and 33 degrees. Just adding fuel lost power, but timing and fuel got us to 760.7hp at 6,400 rpm, even though we gave up about 4 lbs-ft. This was the best overall curve, and from this point on, we kept timing at 32-32.5 degrees and had established a good solid tune for the Holley HP 1000.

Many years ago, Edelbrock produced some dual-lane intake manifolds that appear to be enlarged versions of the factory 427 / 425hp hi-rise intakes. There were several versions, the C-396, C-400 and C-427 for combinations of 4150s and Dominators as well as oval and rectangular pots. But the one we were interested in was the neatest of all. The C-454 is for rectangular port heads and allows a Dominator carb to be utilized and still fit under an L-88 hood! Now this intake is long out of production and is pure swap meet fodder, but in their day, they performed well. When I pulled that intake out, you could hear the collective sighs of all the SAM guys. “Why are we wasting our time?” Most bets had us losing at least 100hp. I mean how could an ancient dual-plane intake designed for 427s and 454s ever stand a chance of feeding a big nasty 555-inch monster? When those intakes were designed, Pro Stockers didn’t even make 700hp! This particular piece was untouched … as in there was a huge mismatch of the smaller intake ports feeding into the killer Dart 335 CNC head ports. We did nothing to it except bolt it on and drop on another out-of-the-box Holley … this time an Ultra HP 1150 Dominator.

Of course, we knew we would lose horsepower. We also knew we were hampering any chance of that Dominator performing to its best, but we needed to see if an intake like this could be a viable solution for a high-performance big-block under a ’Vette hood. When the noise was over, none of us were prepared for the results. There was dead silence in the dyno control room as we stared at the screen. That swap meet special had just made 673 lbs-ft at 5,000 rpm and 739.6hp at 6,200 rpm! At its peak, it was only down 19hp and even at 6,500 rpm it was only down 23hp. Jetting in the Ultra HP 1150 was dead on the money.