All compression ratios based on the following information
1. Head gasket is .039 compressed 2. Piston is .001 down the bore at top dead centre.
All Compression ratios are estimates, based on information available!
Extra deck height will lower the compression ratio.
| PP-BY1412030 | 283 1957-70 Bore:3.875 Stroke:3.00 C.H:1.779 C/R-OEM:8.3:1 Crown:Flat Weight:774g | £222.08 |
| PP-BY1412060 | 283 1957-70 Bore:3.875 Stroke:3.00 C.H:1.779 C/R-OEM:8.3:1 Crown:Flat Weight:790g | £134.98 |
| PP-BY1449030 | 305 1976-86 Bore:3.736 Stroke:3.484 C.H:1.540 C/R-OEM:8.3:1 Crown:Flat Weight:790g | £149.05 |
| PP-BY1482H030 | 305 1982-86 Bore:3.736 Stroke:3.484 C.H:1.540 C/R-OEM:9.5:1 Crown:Flat 4VR Weight:677g | £164.57 |
| PP-BY3441030 | 305 1996-01 Bore:3.736 Stroke:3.484 C.H:1.540 C/R-OEM:9.4:1 Crown:3.13x.040 Weight:677g | £265.24 |
| PP-BY3452HC030 | 305 1996-01 Bore:3.736 Stroke:3.484 C.H:1.560 Crown:2.83x.040 Weight:651g | £235.16 |
| PP-BY1493CSTD | 305 Marine Bore:3.736 Stroke:3.484 C.H:1.540 Crown:3.13x.040 | £195.78 |
| PP-BY1423030 | 327 1962-69 Bore:4.00 Stroke:3.25 C.H:1.654 C/R-OEM:8.7:1 Crown:Flat 4VR Weight:803g | £225.19 |
| PP-BY1423060 | 327 1962-69 Bore:4.00 Stroke:3.25 C.H:1.654 C/R-OEM:8.7:1 Crown:Flat 4VR Weight:821g | £187.69 |
| PP-BY1436030 | 350 1969-70 Bore:4.00 Stroke:3.484 C.H:1.540 C/R-OEM:8.8:1 Crown:Flat 4VR Weight:734g | £161.14 |
| PP-BY1436040 | 350 1969-70 Bore:4.00 Stroke:3.484 C.H:1.540 C/R-OEM:8.8:1 Crown:Flat 4VR Weight:747g | £129.04 |
| PP-BY1436060 | 350 1969-70 Bore:4.00 Stroke:3.484 C.H:1.540 C/R-OEM:8.8:1 Crown:Flat 4VR Weight:750g | £167.66 |
| PP-BY3437HC030 | 350 1969-70 Bore:4.00 Stroke:3.484 C.H:1.540 Crown:Flat 4VR Weight:716g | £191.19 |
| PP-BY3437HC040 | 350 1969-70 Bore:4.00 Stroke:3.484 C.H:1.540 Crown:Flat 4VR Weight:721g | £191.19 |
| PP-BY3437HC060 | 350 1969-70 Bore:4.00 Stroke:3.484 C.H:1.540 Crown:Flat 4VR Weight:733g | £223.63 |
| PP-BY224-2511 | 350 1969-70 Bore:4.00 Stroke:3.484 Crown:Flat 4VR Weight:707g | £19.04 |
| PP-BY1476HCSTD | 350 1971-95 Bore:4.00 Stroke:3.484 C.H:1.540 Crown:3.14x.070 Weight:685g | £213.69 |
| PP-BY1476HC030 | 350 1971-95 Bore:4.00 Stroke:3.484 C.H:1.540 Crown:3.14x.070 Weight:688g | £199.63 |
| PP-BY3462HC030 | 350 Marine Bore:4.00 Stroke:3.484 C.H:1.540 Crown:3.3x.185 Weight:658g | £144.30 |
| PP-BY3470HC030 | 350 Marine Bore:4.00 Stroke:3.484 C.H:1.540 G/PIN:.9273 Rings-1,2,3:1.5-1.5-3mm C/R-OEM:9.4:1 Crown:3.10x.080 C/Rod:5.70 | £397.06 |
| PP-BY3470HCSTD | 350 Marine Bore:4.00 Stroke:3.484 C.H:1.540 G/PIN:.9273 Rings-1,2,3:1.5-1.5-3mm C/R-OEM:9.4:1 Crown:3.10x.080 Weight:652g C/Rod:5.70 | £414.55 |
| PP-BY3457H030 | 350 Marine Bore:4.00 Stroke:3.484 C.H:1.550 G/PIN:.9273 Rings-1,2,3:1.5-1.5-3mm Crown:2.71x.082 Weight:715g C/Rod:5.70 | £168.64 |
| PP-BY1433040 | 396 1965-69 Bore:4.094 Stroke:3.766 C.H:1.747 G/PIN:.9898 Rings-1,2,3:5/64-5/64-3/16 C/R-OEM:9.6:1 Crown:.188 dome C/Rod:6.135 | £303.24 |
| PP-BY1475HC030 | 454 1970-83 Bore:4.250 Stroke:4.00 C.H:1.627 G/PIN:.9898 Rings-1,2,3:5/64-5/64-3/16 C/R-OEM:9.0:1 Crown:Flat2VR Weight:881g C/Rod:6.135 | £368.54 |
| PP-BY1475HC060 | 454 1970-83 Bore:4.250 Stroke:4.00 C.H:1.627 G/PIN:.9898 Rings-1,2,3:5/64-5/64-3/16 C/R-OEM:9.0:1 Crown:Flat2VR Weight:892g C/Rod:6.135 | £252.99 |
| PP-BY3403HC030 | 454 1981-90 Bore:4.250 Stroke:4.00 C.H:1.627 G/PIN:.9898 Rings-1,2,3:2.0x.65 C/R-OEM:9.0:1 Crown:Flat2VR C/Rod:6.135 | £287.29 |
| PP-BY3403HC060 | 454 1981-90 Bore:4.250 Stroke:4.00 C.H:1.627 G/PIN:.9898 Rings-1,2,3:2.0x.65 C/R-OEM:9.0:1 Crown:Flat2VR Weight:892g C/Rod:6.135 | £382.42 |
| PP-BYKB144030 | 305 3.736 3.484 1.561 .9273 5/64-5/64-3/16 10.62 10.18 9.58 638g P/U 5.70 | £344.94 |
| PP-BYKB143030 | 305 3.736 3.484 1.561 .9273 5/64-5/64-3/16 9.34 9.02 8.56 618g F/T 5.70 | £232.46 |
| PP-BYKB157040 | 327 4.00 3.250 1.678 .9273 5/64-5/64-3/16 11.16 10.74 10.08 752g P/U 5.70 | £312.14 |
| PP-BYKB186030 | 334 [305] 3.736 3.750 1.433 .9273 5/64-5/64-3/16 9.44 9.14 8.68 588g D/C 5.70 | £373.90 |
| PP-BYKB260030 | 350 4.00 3.484 1.265 .9273 1/16-1/16-3/16 10.31 9.97 9.44 537g F/T 6.00 | £314.56 |
| PP-BYKB231030 | 350 4.00 3.484 1.561 .9273 1/16-1/16-3/16 10.31 9.97 9.44 587g F/T 5.70 | £380.74 |
| PP-BYKB231040 | 350 4.00 3.484 1.561 .9273 1/16-1/16-3/16 10.35 10.01 9.48 600g F/T 5.70 | £395.74 |
| PP-BYKB193030 | 350 4.00 3.484 1.561 .9273 5/64-5/64-3/16 9.63 9.34 8.90 671g D/C 5.70 | £354.37 |
| PP-BYKB164060 | 383 [350] 4.00 3.75 1.130 .9273 1/16-1/16-3/16 9.70 9.41 9.00 529g D/C 6.00 | £353.15 |
| PP-BYKB164030 | 383 [350] 4.00 3.750 1.130 .9273 1/16-1/16-3/16 9.57 9.30 8.89 510g D/C 6.00 | £435.29 |
| PP-BYKB164040 | 383 [350] 4.00 3.750 1.130 .9273 1/16-1/16-3/16 9.61 9.35 8.92 517g D/C 6.00 | £353.15 |
| PP-BYKB253030 | 383 [350] 4.00 3.750 1.433 .9273 1/16-1/16-3/16 10.88 10.51 9.97 568g F/T 5.70 | £405.24 |
| PP-BYKB253040 | 383 [350] 4.00 3.750 1.433 .9273 1/16-1/16-3/16 10.91 10.56 10.02 592g F/T 5.70 | £414.47 |
| PP-BYKB253060 | 383 [350] 4.00 3.750 1.433 .9273 1/16-1/16-3/16 11.01 10.65 10.09 584g F/T 5.70 | £380.39 |
| PP-BYKB147030 | 400 4.125 3.75 1.433 .9273 5/64-5/64-3/16 10.2 9.89 9.45 688g D/C 5.70 | £416.16 |
| PP-BYKB203030 | 454 4.25 4.00 1.645 .9898 5/64-5/64-3/16 9.09 868g P/U 12cc 6.135 | £447.70 |
| PP-BYKB389034 | 540 [454] 4.50 4.25 1.270 .9898 1/16-1/16-3/16 8.94 730g S/D 6.385 | £346.80 |
| PP-BYKB717030 | 350 4.00 3.484 1.561 .9273 1/16-1/16-3/16 10.44 10.10 9.55 632g F/T 5.70 | £473.94 |
| PP-BYKB718030 | 383 [350] 4.00 3.750 1.130 .9273 1/16-1/16-3/16 11.16 10.76 10.20 542g F/T 6.00 | £495.50 |
| PP-BYKB718040 | 383 [350] 4.00 3.750 1.130 .9273 1/16-1/16-3/16 11.18 10.81 10.23 F/T 6.00 | £419.42 |
| PP-BYKB735030 | 383 [350] 4.00 3.750 1.433 .9273 1/16-1/16-3/16 9.63 9.36 8.93 618g S/D 5.70 | £475.61 |
| PP-BYKB735040 | 383 [350] 4.00 3.750 1.433 .9273 1/16-1/16-3/16 9.68 9.40 8.97 628g S/D 5.70 | £468.21 |
| PP-BYKB762030 | 400 [377] 4.125 3.484 1.261 .9273 1/16-1/16-3/16 10.96 10.59 10.02 F/T4.8cc 6.00 | £446.74 |
| PP-BYAJG580 | 427 [350] 4.125 4.000 1.115 .9273 1/16-1/16-3mm 10.50 10.20 9.73 S/D19.5cc 6.20 | £462.72 |
| PP-BYKB789060 | 496 [454] 4.25 4.250 1.270 .9898 1/16-1/16-3/16 10.37:1 P/U 20cc 6.385 | £472.50 |
| PP-BYKB787060 | 496 [454] 4.25 4.250 1.270 .9898 1/16-1/16-3/16 8.23 P/U 12cc 6.385 | £472.51 |
| PP-BYKB814034 | 540 [454] 4.50 4.250 1.270 .9898 1/16-1/16-3/16 10.27:1 738g P/U 10cc 6.385 | £463.71 |
| PP-BYKB808034 | 572 [454] 4.50 4.50 1.395 .9898 1/16-1/16-3/16 11.43 P/U 17cc 6.535 | £472.51 |
| PP-BYKB806034 | 572 [454] 4.50 4.50 1.395 .9898 1/16-1/16-3/16 9.86 F/T 3cc 6.535 | £437.80 |
| PP-BY13720030 | 350 4.00 3.484 1.260 .9273 1/16-1/16-1/8 11.59 11.16 10.49 566g P/U 6.00 £358.38 | £602.70 |
| PP-BY13720040 | 350 4.00 3.484 1.260 .9273 1/16-1/16-1/8 11.65 11.21 10.53 564g P/U 6.00 | £510.68 |
| PP-BY14210030 | 395 [350] 4.00 3.875 1.219 .9273 1/16-1/16-3/16 F/T -4cc 5.85 | £502.89 |
| PP-BYL2441F030 | 350ci, 4.00bore, 3.484 stroke, 1.560 C.H, 0.9273 G/Pin, 5/64-5/64-3/16 Rings 1-2-3, C/Ratio 8.35:1 with 64cc heads, C/Ratio 8.14:1 with 67cc heads, C/Ratio 7.8:1 with 72cc heads, Weight:722g, Grown D-Cup, 5.7 C/Rod. Price Each | £63.17 |
| PP-BYR71 | Pins 2.25 long x .927 diam, 88g | £87.39 |
| PP-BYR60 | Pins 2.50 long x .927 diam, 98g | £103.83 |
| PP-BYR61 | Pins 2.75 long x .927 diam, 107g | £99.43 |
| PP-BYR20 | Pins 3.00 long x .927 diam, 118g | £120.04 |