About SRH

Chad Speier & SRH

Custom induction systems specifically tuned to your engine and type of racing.

My history

20+ years of porting

Chad Speier has been porting cylinder heads for well over 20 years, with positive results in all forms of racing. Chad began porting heads in the mid ’90s after spending several years at Madcap Racing Engines in Denver, Colorado, and gained CNC experience working for GRP and MGP, the world’s leader in billet connecting rods. In December 2002 he opened a full shop and has been porting cylinder heads full time ever since.

A businessman who always puts customer satisfaction first, Chad believes that in any industry, it’s all about relationships. Absolutely no pressure. His purpose is to produce heads sized to your combo — heads the everyday racer can afford — by applying the critical changes: valve size, throat size, bowl and cross-sectional area. Bigger isn’t better. Port shape and average velocity are KING over raw flow.

Close-up of a finished combustion chamber and valve seat

My mission

To help people make an informed decision on any cylinder head purchase — through SRH or another company. Competitive prices, growth by referral, and every available resource aimed at 100% customer satisfaction.

My promise

If heads you buy or have ported by SRH don’t perform like we discuss, send them back and I’ll work on them until they do. Buy new SRH-logo heads and I’ll trade back for them on newer offerings.

The flowbench “conspiracy”

A flow bench isn’t the end-all, but with pitot probing and simple math it builds a database that proves out every time. Recommended reading: Harold Bettes, Engine Airflow.

The SRH 2002 Chevy Cavalier drag car

SRH Racing

We race what we build

  • Car2002 Chevy Cavalier
  • Engine1970 350/360 hp LT1
  • ClassNHRA GT/FA
  • TransTH200 3-speed

Shop tools: Exacta DD valve job, Sunnen VR7000, Winona CBN surfacer, Saenz D680 flow bench w/ Audie, Buxton digital spring tester.

SRH Nation

Dyno & track results

As published on the current site. Most builds are not max effort — also ask about ETs and lap records!

EngineResultHeads / induction
347 SBC 12º870hpv615X
347 SBF 20ºSTREET ENGINE 575hpvPFSBF
354 SBC 14º Pro Action910hp@9000—
355 SBC 23º630hpv2.50PF/23º
365 SBC 23º625hpv2.50PF/23º
365 SBC 23º780hp/595tqv3.00PF/23º
377 SBC 23º675hp/505tqV2.70PF/23º
379 SBC 23º540hp/515tq Pump GasV2.35PF/23º
380 SBC 23º9.50at3000lbsv2.50PF/23º
380 SBC 23º10.10at3500lbsv2.70PF/23º
380 SBC 14ºCURRENT A/ND RECORD HOLDER—
380 SBC 23ºSWJF 7.27at185, RECORD HOLDER—
383 SBC 23º530hp (v2.50BI/23º) STREET ENGINE—
383 SBC 23º512@5200tq 570@6200 Pump Gasv2.50BI/23º
383 SBC 23º550hp/510tq pump gasv2.50PF/SB
383 SBC 23º500hp/510tq pump gasv2.35PF/SB
383 SBC 23º655hpv2.50BI/23º
383 SBC 23º580hpPF "ECONO"
388 SBC 23º540hp FT camPF "ECONO"
388 SBC 23º672hp/556tqv2.50PF/SB
388 SBC 23º660hp/531tq195cc Hand Ported
390 SBC 23º715hpv2.72AR/23º
400 SBC 23º755hpv2.70PF/23º
400 SBC 13º1000+@9800v3.00PF/13º
400 SBC 23º700hp/600tqv2.72AD/23º
401 SBC 23º1009whp (v2.72AR/23º) 8.90@3750lbs—
406 SBC 23º Pump Gas600hpRHS "ECONO"
406 SBC 23º750hpv2.50PF/23º
406 SBC 23º3240lb. 6.06/9.87v2.50PF/23º
406 SBC 23ºPump Gas- 602.3@6450 and 548.9@5100v2.50BI/23º
406 SBC 23º680hp/544tqv2.50BI/23º
406 SBC 23º—v2.70PF/23º
406 SBC 23º560at6400/500at4800 pump gasv2.50PF/23º
408 SBC 23º5.76at2650lbsv2.50PF/23º
408 SBF685at7100v2.50AB/SBF
409 SBC 23º266/274 710@7000/598@5500v2.70PF and Burr Manifold
406 SBC600RWP (v2.50PF/23º) pump gas—
414 SBC5.17at3180lbs w/IS Sledgehammerv2.80ED/RR
HEMIB/ND NATIONAL RECORD HOLDER—
418 SBC5.04at138at3000 w/485 platev2.70PF/23º
421 SBC 23º720hp (v2.70PF/23º) NITROUS BUILD—
421 SBC 23º630hp pump gas 237 camv2.50PF
421 SBC 23º730hp/600tqv2.70PF
421 SBC 23º5.40at129at3125 (v2.70PF/23º) 300 shot—
421 SBC 23º680@7000/600@5600v2.50PF and as-cast 2892
421 SBC 23º5.71at2800, 6600rpmv2.50PF/23º
421 SBF Pump Gas670hpv2.50AB/SBF
422 SBF Dirt Modified780hpv3.10BT/FCV
427 SBC Pump Gas9.60's at 3300 (v2.70PF/23º) footbrake S10—
427 SBC Pump Gas.580 lift 609@6400v2.50PF.23º
427 SBF4.90's in NITROUS Xv7721/15º
428 Pontiac—v2.66/EMC
430 SBC 13º910hp/675tq in N2O trim!—
434 SBC 23º757@7000/611@5600v2.70PF and Burr manifold
434 SBC 23º760@7200/620@5800v2.70PF and Burr manifold
434 SBC 23º ported RHS275R, 5.40at3080, pump gas—
434 SBC 23º702@6900/592@5200 pump gasv2.70PF/23º
434 SBC 23º755hp (v2.70PF/23º) NITROUS BUILD—
434 SBC 23º5.50@122at 2700lbsv2.70PF/23º
434 SBC 23º5.55@122at2600lbs w/.680 liftv2.70PF/23º
434 SBC 23º702@6800/592@5200 w/unported manifoldV2.70PF/23º
434 SBC 23º5.56@123at 2550lbsv2.72AR/23º
434 SBC 23ºE85- 710hpv2.50PF/23º
434 SBF 20ºPUMP GAS 699.9hpv2.80PF/SBF
434 SBF 20ºUMP A-Mod 629@5400/767@7100v2.80PF/SBF
436 SBC 23º785@7400/614@6200v2.70PF and 2892
437 SBC 13ºSBC- 1022hp@8500/677@7300v3.00PF/13º
438 SBC 23º827@6700/ 621@5300v3.00PF/13º
440 SBF 15º592@7000/805@7900 PUMP GASv3.10BR/15º
440 SBC 13ºSBC- 910hp at 7500v3.00PF/13º
440 SBC 23ºPUMP GAS 750@7300v2.70PF/23º
440 SBC 13ºSBC- 960hp at 7900v3.00PF/13º
440 SBC 23ºSBC- 810hp at 7500v3.00PF/23º
454 SBC 23ºSBC- 780hp at 7400v3.00PF/23º
482 BBC922at8-8400/630at64-8000v4.00ID/BBC
496 BBC960hpv4.20IR/BBC
505 BBC1040hpv4.20IR/BBC
510 BBC1040hpv4.00ID/BBC
512 BBC1010hp@8100, 707tq@6200v4.00ID/BBC
512 BBMPump Gas 652.8@5700 and 664.5@4450v2.60/EDRPM
520 BBM615/660 Street Enginev2.60/EDRPM
548 BBC1908/1450 w/ported Pro-Filer and Hi-Helix—
565 BBC1025hp@7500v4.00AD/BBC
565 BBC1100hp truck pullerv4.20IR/BBC
588 BBC1090hp NITROUS BUILDv4.200AR/BBC
632 BBC1098hp@7000v4.00ID/BBC

Tech corner: sizing formulas

  • MIN CSA = (Bore × Bore × Stroke × RPM × .00353) / 613.8 (.55 Mach)
  • Average CSA = Port Volume cc / (Port Centerline Length × 16.387)
  • Port Volume cc = Average CSA × Port Centerline Length × 16.387
  • FPS = (Flow CFM × 2.4) / Average CSA
  • CFM demand = CID × RPM × .0009785 / # of cylinders

Example: a 434 SBC at 7000 rpm needs ~2.78 in² MIN CSA ≈ 248 cc at a 5.45 port length.

In the news

Past work

Past work gallery

Heads, chambers and manifolds that have come through the shop.

CNC machined combustion chamber
Pair of ported intake runners
ProFiler head combustion chambers
Super Stock head ports
Burr-finished manifold plenum
Dart head chamber after porting
LS3 CNC ported intake port
ProFiler 13 degree ports

Ready to make more power?

Tell Chad about your combo — heads, manifold, class and RPM goal.

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