BB Chevy Holley Strip Dominator

[Ron Miller]

Question for the full-time head & intake porters. I'm building a BB Chevy 496 street/strip engine for a friend. Build consist of GM 781 oval port heads with some port work. Valve sizes are 2.250 intakes 1.88 exhaust. The cam is a Comp Cams Xtreme Energy XR286R with a @ .050 duration 254/248, lift .653/.666 installed at 106 centerline. He has an older BB Chevy Holley Strip Dominator oval port intake that has some intake porting/matching. It has been milled on the intake face and fits the heads/assembly real good. Will intake be enough to support the C.I.? Are we leaving power & torque on the table? Can this intake work and what other mods can be done in the plenum. Currently, it is stock. Also what size carb would you Guys recommend? Thanks for looking.

[F-BIRD'88]

There is power to be had with a bigger custom grind cam from that XR mech street roller series. But you can start with that one. The intake is good. Needs a big carb. Possible a dominator on a adapter.

[dondon]

I did a swap on the dyno between a holley strip dominator and an edelbrock air gap rpm. Both ported by myself. both oval ports. I thought strip dominator would make more power, but the air gap rpm made 10 hp and 10 tq more. My engine was a 427 .030 390 hp, ported 702's with 2.19 / 1.88s with 255@ .050 .620 solid lifter, 850 carb. It made 548 hp, 515 tq, with the air gap. Your results may very.

[C.A.R.E.]

Dynoed street 496 XR294HR10 ported 781 2.19-1.88 10.15-1 pump gas 950HP. Holley 300-4 peak 622chp@5800 645ctq@4600 avg 3500-6000 605ctq 546chp. Edelbrock Victor JR Oval Port peak 638chp@ 5800 658ctq@ 4700. Avg 3500-6000 613ctq 553chp. Both manifolds were stock, no porting. With 8 O2s the Holleys center 4 cylinders were rich. Tried to post dyno sheets but file was to large. Send me a email address and I can send them to you.

[Ron Miller]

Dynoed street 496 XR294HR10 ported 781 2.19-1.88 10.15-1 pump gas 950HP. Holley 300-4 peak 622chp@5800 645ctq@4600 avg 3500-6000 605ctq 546chp. Edelbrock Victor JR Oval Port peak 638chp@ 5800 658ctq@ 4700. Avg 3500-6000 613ctq 553chp. Both manifolds were stock, no porting. With 8 O2s the Holleys center 4 cylinders were rich. Tried to post dyno sheets but file was to large. Send me a email address and I can send them to you.

Thanks for the info. Did you ever consider adding runner extensions - dividers? Years ago I looked a modified Strip Dominator. It had the runners extension with a 1" spacer grounded and all blended into the plenum. I wish I had taken some pictures and measurements. By all means, Please send me what you have. My e-mail address is rmiller249@comcast.net.

Thanks Again,

[Ron Miller]

Guys, Thanks for all the replies and info.

[Walter R. Malik]

Dynoed street 496 XR294HR10 ported 781 2.19-1.88 10.15-1 pump gas 950HP. Holley 300-4 peak 622chp@5800 645ctq@4600 avg 3500-6000 605ctq 546chp. Edelbrock Victor JR Oval Port peak 638chp@ 5800 658ctq@ 4700. Avg 3500-6000 613ctq 553chp. Both manifolds were stock, no porting. With 8 O2s the Holleys center 4 cylinders were rich. Tried to post dyno sheets but file was to large. Send me a email address and I can send them to you.

People must remember that this Holley intake was designed in the late 70's and at that time, there was none better.

[C.A.R.E.]

Our 300-25 SBC was modified by Lingerfelter back in the early 80s but never tried a BBCwith divider extensions.

[Ron Miller]

Our 300-25 SBC was modified by Lingerfelter back in the early 80s but never tried a BBCwith divider extensions.

Thanks for the e-mail, dyno charts.