DeTomaso Mailing List: July 97, Message #111
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> Ron Graves just mailed me a copy of a 10/93 Super Ford Magazine article > which tested several intakes on a serious high compression stroked 351C. > Here's the summary of the best indicating where they made the peak > numbers (with a *). : Here's some more detail on the Super Ford article. I've been keeping summaries of Cleveland related magazine articles for a while now and just happenned to have this one handy. Later, Dan Jones Super Ford, October 1993, "Planes of Power" ------------------------------------------- Intro This article covers a dyno comparison test of several single and dual plane intake manifolds on a drag race 13.7:1 compression ratio 377 cubic inch 351C-4V. Dyno numbers are provided in 250 rpm steps from 2750 to 6750 rpm. I have reproduced only the peak figures here. Carb Blueprinted Holley 850 CFM double pumper for all intakes except FPP 4146, which used a Holley 1050 CFM Dominator. Intakes Factory Boss 351 aluminum low rise dual plane (D1ZX-9425-DA) Edelbrock Torker low rise single plane Weiand X-celerator low rise single plane Offenhauser Port-o-Sonic single plane Holley Strip Dominator (300-13) high rise single plane FPP 4145 high rise dual plane FPP 4145B high rise dual plane FPP 4146 high rise dual plane Heads DOAE 4V closed chamber with light chamber and port work, 64 CC's 2.19"/1.71" FPP stainless steel valves with under cut stems milled for FPP guide plates and screw in studs Boss cast aluminum valve covers Cam and Valvetrain Madden dual pattern roller CT5 cam, 264/270 degrees duration @ 0.050" lift, 0.723 inch lift FPP true roller timing chain and gears Smith Brothers custom length push rods Sig Erson E915057 springs and dampers, installed height 1.875" @ 210 lbs open 1.250 @ 510 lbs FPP titanium retainers Crower stainless steel roller rockers Jomar stud girdle Isky lash caps B&B valve covers spacer and studs Block and Reciprocating Assembly 377 inch stroker kit (stock 3.5" stroke increased to 3.7", 0.030 overbore) from the Performance Shop, offset ground stock 2.311" rod journals to 2.1" to accomodate 5.7" center-to-center Chevy rods, journals widened to 1.900" inches to accomodate wider rod big ends, rod small ends bushed to Ford 0.912" pin diameter, pins are full floating, L2348F TRW pistons with 1.645" compression height resulting in 0.005" deck clearance, Speed Pro plama moly coated rings, dry moly coated pistons Genuine Fisher damper FPP 4 bolt main cap kit on 2 bolt main block (DOAE-J) FPP screw-in freeze plugs FPP main and head stud kit FPP high volume oil pump and shaft Oiling System Boss 351 pan (integral windage tray) on dyno Canton 7 quart in car Exhaust 2" primary tube diameter Cooling Weiand aluminum water pump Ignition Stinger ignition with 36 degrees total advance MSD dyno box Boss 351 Aluminum Intake Manifold (D1ZX-9425-DA) RPM TQ HP VE 4250 422 6250 451 6750 104.8 On this engine, the factory Boss 351 intake makes over 400 ft-lbs of torque from 3500 to 5000 rpm. The engine gains 70 ft-lbs from 3000 to 3250 rpm (comes on like a light switch). The basic differences between factory 351C intakes are in materials (aluminum or cast iron) and carb flange (square or spread bore). Torker 351 low rise single plane RPM TQ HP VE 4750 421 6750 480 110.5 The Torker makes over 400 ft-lbs of torque from 4250 to 6000 rpm. Low end response is good ("a single plane that thinks it's a dual plane"). FPP 4145 dual plane (mfg by Blue Thunder) RPM TQ HP VE 3750 425 6250 490 6750 105.9 The best performing dual plane ("a dual plane that thinks it's a single plane"), second only to Holley Strip Dominator in max hp. FPP 4145B dual plane RPM TQ HP VE 4750 429 6250 471 6500 105.1 This intake is the same as FPP 4145 except the heat risers are blocked, the plenum divider is cut down one inch and the carb flange enlarged. Performance genrally suffered from these modifications. FPP 4146 dual plane RPM TQ HP VE 5000 408 6250 462 6750 92.2 This intake is the same as FPP 4145 except the carb flange is machined for for a Holley Dominator carb (1050 CFM). Performance took a big hit. Holley Strip Dominator (300-13) RPM TQ HP VE 5000 435 6250 498 110.6 This high rise single plane race intake generated the biggest overall numbers, and generated over 400 ft-lbs of torque from 4250-6250. This intake is no longer in production. Offenhauser Port-o-Sonic RPM TQ HP VE 4500 398 6250 441 6750 103.9 This single plane intake didn't work well with this particular combination, giving up 10 HP to the factory intake and 57 hp to the Holley Strip Dominator. Offy indicated the would prefer an increase in lobe lift, decrease in rocker arm ratio, and longer duration. Weiand X-Celerator RPM TQ HP VE 5250 410 5750 410 6500 473 107.9 This is another single plane that thinks its a dual plane, generating over 390 ft-lbs of torque from 3250 to 6250 rpm. Comments I'd like to see a similar test performed on a street oriented, stock displacement, rational compression 351C. I assume the increased displacement and high compression ratio make the single plane intakes perform better at lower RPM than they would on a stock dislacement engine. The rule of thumb that single plane intakes are better on the high end and dual planes are better on the low end was not all that valid in this instance. Generally, the high rise manifolds outperformed the low rise rise manifolds. I'd also like to see a comparison trading off height in the intake for height in the air filter (i.e. Does a high rise with 2" tall filter still out-perform a low rise with 3" tall filter?). ==============================================================================