88bluchevy

I have an 87 complete roller motor equipped with the xr276hr cam, air gap intake, patriot vortec heads (2.02/1.60) msd ignition and an edelbrock 650 carb. Some people say its going to make 380 to 400 at the flywheel, but after doing research i found where popular hotrodding built the same setup with the exceptions as follows:
cylinder heads-Enginequest "Lightning" CH350C cast-iron Vortec-style
intake-Professional Products Crosswind two-plane intake manifold
carb- holly 750
cam-COMP Cams hydraulic roller single-pattern grind, with 224 degrees duration (at .050), 108-degree lobe separation angle

Also they used 1.6 rockers where as mine are still 1.52.

So my question is how did they get 441 horsepower at the flywheel, when ive got better flowing heads and some say its only going to make 380?

redsilverado05

I'm not an engine building and developing expert but from the info I just read I could give you 100's of reason's why and why not it didn't make as much hp, less hp, or more hp.

PathfinderJr

iTrader: (6)

post up the flow data on your heads and the heads used in that other build you're referencing. But right off the bat, I'm telling you, that 650 carb is gonna be holding you back.

Also, the narrow lobe separation is gonna make that other power curve peakier which could result in a "spike" of sorts that hits that 441hp mark.

88bluchevy

EQ Heads-
Lift Intake Exhaust
0.100 60 54
0.200 117 102
0.300 173 134
0.400 216 152
0.500 225 162
0.600 232 169
0.700 237 172

My heads-

Lift Intake Exhaust
.100 74 50
.200 140 99
.300 202 145
.400 235 175
.500 241 183
.550 243 185
.600 246 190

L7 Sierra

I'd say 420 easy, but they may run more compression which is roughly 10-15 per 1 point or any other magical things could happen. Plus they may have built a hot street motor where you tamed it down a bit with compression to run cheaper gas or compensate for a heavy vehicle. I built a couple of the Car Craft agent 87 style motors back before marriage when I could waste every dime randomly, and damn what a difference going from 8.5 to 10-1 compression makes. Maybe the HP figures would say something else, but SOTP and track times verified it for me. Plus with increased MPG it would off set the 20 cent difference, but this assumes that is the only difference between the 2 motors.

But they usually run no accesories during there test and 1/2 the time a electric water pump. your 1.52 vs there 1.6 on an SBC is usually good for 10-13 hp provided you were not on the very magical edge of over caming somehow. I did that one time with 882 heads and a big Crower 525 cam and lost driveability everywhere, and hp up till 4000+rpm. Even after tuning. Plus they are tuning for one day where you'd have to tune for a truck, the rain, wind, cold, and maybe even just the fact its wednesday and you need to go somewhere.

Plus some so called experts have never gotten over the fact ported camel humps flow like ported 882 heads which flow like dogs compared to any of the Iron eagle series heads which I have probily owned the most of by a long shot. Plus the upgrade Platinum is good for another 15 horse, and its still an original dog leg style head and not the raised runner like the Vortec.

88bluchevy

I did the desktop dyno and put in all my info to the ''t'' and it was showing 457hp and 489ft/lbs. If I can get 420-430 that would be great. In the coming year I'll be swapping out the th400 for a 700r4 with a 3200 stall so that should make things interesting.

L7 Sierra

Thats a lot of stall for a 700r4 with a motor that should start to pump really hard about 2800rpm.

What gears do you plan on having?
Also what tire size do you plan to run?

88bluchevy

Ive got 3.90 gears with the detroit trutrac and Im plan on running some 28'' drag radials either the mickey thompson et streets or nitto drag radials.

Burgundy&TanMan

I dont know if he said but his compression should be somewhere around 10.3-1.