All the testing in our stories was done with the old McClelland short-block rebuilt by JMS Racing Engines. The combo Is as basic as it can get and easily duplicated. The only nonstock components In the short-block are ARP rod bolts and Speed-Pro forged pistons, PN L2353F, in a 0.030-inch overbore (stock bore is 4.3125, so our bore Is 4.3425 for 462 ci). The Speed-Pro slugs are the lowest-priced forged pistons you can buy for the 455; TA Performance sells them for $429.95 a set. However, they do have some drawbacks, including an old-school V&i-inch ring pack and a hefty 758-gram weight. Also, the dished Speed-Pros do not have valve reliefs in 'em, but TA Performance also sells precut pistons for an extra $85, and that's what we used. For just an extra $235 to $250, you could get modern, lightweight, custom forgings with '/i6-inch rings, and the extra money could be well worth the opportunity for more compression.
The Buick 455s were launched in 1970 with 10.0:1 to 10.5:1 compression, but that fell to 8.5:1 In 1971 and then to 8.3:1 before the engine was discontinued after the '76 model year. On our test engine, the compression represents what you'll get from a stock '71 to '76 junkyard 455 or what is running in your Buick right now. The Speed-Pro L2353F pistons start life with 27.8cc dishes, then add another 3 to 4 cc for the custom valve notches, bringing the total to about 32 cc. The compression height is 1.975, the stock rods are 6.600 inches, the stock stroke Is 3.900 Inches, and the production deck height is 10.57 inches. That adds up to pistons that are 0.045 in the hole, but JMS decked the block 0.005, so the real-world number is a poor 0.040 below the deck. The Fel-Pro Performance PN 1125 head gaskets have 4.385-inch bores and a 0.041-inch compressed thickness. Work those numbers with
I he Hooker headers are PN 1204HKR, and we wanted something more retro than ceramic s.lver, so Jet-Hot made them blue for us. Jet-Hot can also do red, gray, green, and black We're not sure why we didn't do the engine in Buick red.
Both cams we tested were flat-tappets, and while TA Performance supplied good, hard-faced lifters, we still took the precaution of breaking them in with the fairly new TB Zinc-Plus oil additive from Lucas.
This month we'll kick it off with cam and intake testing using stock iron Stage 1-style heads, and next month you'll see how the iron heads stack up against the Edelbrocks and the entry-level aluminum offerings from TA Performance. Speaking of TA, we've got to thank Mike Tomaszewski over there, as well as local Buick fan (and owner of a 9-second, naturally aspirated GS455) Bruce Kent, both of whom loaned us parts and expertise.
Our Holley 750 Street HP carb is fitted with a pair of Adjust-A-Jet blocks from Percy's High Performance. These eliminate the jets and make fuel-curve tuning super simple with just a turn with a screwdriver.
Stare long and hard at this shot of the Edelbrock B4B (.left) and Performer intakes and you won't see a whole lot of difference other than the carb-pad location. The dyno found none.
the 70cc chambers in the iron heads used this month and the compression ratio is just 8.77:1.
The heads we used are the stock, reconditioned units from TA Performance, and they use the Stage 1 valve sizes of 2.125/1.750 inches. The regular production 455 heads are the same casting as Stage 1 heads but use smaller 2.00/1.625 valves; TA uses the '74-and-earlier castings and opens up the valve size, just as the factory did. The 75 to '76 castings have factory 78cc chambers and are never used by TA. The '70 heads are 68 cc, and the '71 to '74 units have 71cc chambers that are milled to 69 to 70 cc during the rebuild process.
Our engine uses a bone-stock oiling system, though we found that even the low-volume oil pump gear needed to be shaved 0.010 inch to avoid an interference problem with the oil pump cover.
All our testing was done using an internally balanced flywheel borrowed from Bruce Kent, a Meziere electric water pump, Rockett Brand 91-octane gas, an MSD ignition, E3 spark plugs, and a set of Hooker headers coated by Jet-Hot. The headers are for a Skylark, feature l7/s-inch primaries and 3-inch collectors, and were run with 18-inch collector extensions. We used a Holley 750-cfm Street HP carb for every test, and it was determined through testing that 32 degrees of total timing made the most power.
SMALL CAM, DUAL-PLANE INTAKES
Our first round of dyno tests used the TA Performance hydraulic flat-tappet cam known as the TA-212. It specs out at a tame 218/230 degrees of duration at 0.050 tappet lift. The lobe-separation angle is 112 degrees, and valve lift is 0.459/0.470 inch using stock replacement shaft-style rocker arms (Sealed Power PN R857) with a 1.55:1 ratio.
Using what is perhaps the smallest cam seen in CC this decade, we ran four intakes across the 455: an Edelbrock Performer, an Edelbrock B4B, a TA Performance SP1, and a TA Performance SPX. Both Eddie units were dual-planes, and both TA castings were single-planes.
Interestingly, we inspected the two Edelbrock intakes and the only difference we could see in them was the shape of the carb pad and the fact that the Performer places the carb about 3/s inch rearward as compared with
For accessories, we used a polished, 42-gph electric water pump from Meziere (WP126UHD) and an MSD Billet Plus distributor (PN 8517) triggering a Digital 7 box.
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