This engine came to me by way of Tim Meyer, who was going to rebuild it for this customer but lost his engine building guy, so the customer contacted me. Tim's shop is in Fairmont MN, so on one of my trips his way I picked it up. The engine had been assembled by the customer but never run, because there had been some issues on assembly. It was completely torn down when I got it, so I went through it from the ground up. I found lots of little problems that could have spelled disaster, which I will detail below, but in the end the engine went together and ran fine today on the dyno.
I will post the dyno results tomorrow night (Tuesday 2/25/19). In the meantime, feel free to guess the HP and torque, on both 110 octane race fuel and 91 octane pump premium with 10% ethanol; I ran it both ways. Also, you can try to guess the average vacuum at 850 RPM idle with this setup.
The engine is a 0.030" over C scratch 428 block with 428 rods, ARP bolts, and Probe forged pistons, with the normal 5/32" moly top ring, cast second, and 3/16" oil ring package. When I got the engine Tim Meyer told me that there was a question about main and rod bearing clearances being too tight, so I checked them and sure enough, they were WAY too tight, as low as 0.0008" on the rods and just over 0.001" on the mains. I took the crank in to have it touch-up ground, and then the clearances came in at .0018" to .0025" on the mains and rods. When assembling the short block I decided that I'd better pull the rings off the pistons (they had already been installed) and check the end gaps. When I pulled the rings off I found that all the top rings had been installed in the second ring groove, and vice versa! Could have been a minor issue
After correcting that the short block went together uneventfully. However, I also noticed that the frost plugs were the 1-3/4" ones, so I got some 1-49/64" frost plugs and installed those instead. I had previously opened up the oiling passage from the pump to the oil filter adapter, and tapped all the press-in plugs for screw-in pipe plugs, so I think the short block is pretty solid.
The heads are bone stock Edelbrocks. I measured the chamber volume at 73cc, and with the 4cc eyebrow in the pistons, static compression ratio calculated out to 10.9:1. The customer had bought the whole Edelbrock performance package except for the intake, so he had the Performer RPM cam and lifters. But he wanted to run power brakes, and my own experience with the Performer RPM cam was that it had very limited vacuum, so I suggested a cam change. We decided on a single pattern hydraulic roller stick, Comp Cams lobe 3613, which has advertised duration of 282, duration at 0.050" of 230, and 0.555" lift. The lobes are on 110 degree centerlines, and the cam is installed 4 degrees advanced (106 ICL).
I installed and degreed the cam and the timing set, and then installed the front cover and stock balancer, but discovered a problem with the windage tray. It looks like it was one of those cheap ebay things, and when it was installed the rod nuts would hit the tray on the way around. Turned out that the louvers in the windage tray were punched out wrong, and were actually facing in towards the crank, rather than out towards the oil pan. I would theorize that they put the sheet that makes up the windage tray in the louver press first, then bend it in a different fixture, and whoever did this probably put the sheet into the bending fixture upside down. Anyway, after some creative work with a ball peen hammer I was able to get the louvers bent down into the correct position, and then the oil pan went on without any drama. By the way, this engine uses a high volume oil pump and a stock pump drive, plus a Milodon pan and pickup. Oil capacity is just about 7 quarts.
In addition to the new cam we also sprung for some Morel hydraulic roller lifters. Pushrods were 5/16" Smith Brothers, and we replaced the Edelbrock spring package with Comp beehive 26120 springs, in an effort to get this engine to rev a little higher than most hydraulic cam engines. The rockers were a Harlan Sharp setup, with their end stands and shafts.
For an intake we used an Edelbrock Streetmaster, and I port matched the manifold to the heads, and opened up the plenum per the usual process on these intakes. The carb is an 800 double pumper rebuilt by Holley, sitting on a 1/2" four hole spacer. Headers are Hooker Super Comps for a Mustang, with 1-3/4" primaries and 3" collectors. Ignition is handled by a Mallory Unilite distributor and some kind of a chrome coil, fired through the MSD Digital 6 on my dyno.
So, to recap:
- .030 over 428 block
- 10.9:1 forged pistons, standard ring package
- Stock Edelbrock heads
- Comp hydraulic roller cam, 282/282, 230/230 @ 0.050", 0.555" lift, 110 LSA, 106 ICL
- Port matched Streetmaster intake
- Holley 800 double pumper carb, 1/2" 4 hole spacer
- Hooker Super Comp headers, 1-3/4" primaries, 3" collector
I also experimented with a 1" Super Sucker on the dyno, and will report the results from the best pulls, regardless of the spacer, on pump gas and race gas. A picture of the engine on the dyno is below. Any questions on the combination, let me know, and good luck with your guess!
Edit: Forgot to add, I will be reporting corrected numbers. It was very cold in Minnesota today, and the barometric pressure is high. The very unusual result of these weather conditions is that the corrected horsepower and torque is actually LESS than the raw power values. This is a function of the high pressure and very cool air that the engine is breathing. Correction factor for most of the pulls was 0.996 or so.
