Despite the fact that the 350 Pontiac engine generally garners little attention in the hobby, HPP still receives a fair amount of questions regarding building them up. Some owners want to retain numbers-matching block status and add some tire-smoking power, and others desire to be different and not simply perform a traditional 400 or 455 swap in an effort to increase performance.
For those who fit into either category, Ken "Ace" Brewer from Pacific Performance Racing (PPR) has an answer. PPR, home of Tomahawk Performance Products, has just released a brand new 4.00-inch stroker package for the plentiful and very-inexpensive-to-buy 350 engine that transforms it into a 383-cube thumper. Follow the recipe outlined here, and you can look forward to 462 horsepower at 6,100-rpm and 436 lb-ft of torque at 4,400 rpm. The beautiful part is that the combination employs a lightweight reciprocating assembly for a quicker rate of rev, a 9.6:1 compression ratio for pump gas, valve sizes that quiet the old complaint of too much shrouding in the small bores, and it's affordable. How affordable? Does $1,595.95 (under $1,400 with 5140 rods) for a complete balanced Ultra Lite rotating assembly with forged pistons and forged steel rods ring your bell?
Some of you may be asking, why not just build a 400? That's a reasonable question, assuming you have one at the ready. But the fact that few Pontiac hobbyists seem to want 350s makes cores very cheap, if not free, and the 350/383 could be considered the underdog in any race against a larger engine from any camp, so there is the spoiler factor as well. If nothing else, Pontiac fans have a new number to play with.
Think how much fun it will be upstaging the Bowtie and Mopar brigades, who owned exclusive 383 bragging rights...until now. Remember, this thing actually cranks out some power. If it didn't, we wouldn't waste time telling you about it. Now go pull a 350 out of the scrap bin and get started!
Any '68-'77 350 block that passes the usual magnaflux and pressure test inspection is plenty strong enough for the job. Ken Brewer says that only blocks cast between 1970 and 1975 feature the desirable five-boss motor mount layout, as shown. You can plug these blocks into any '61-'79 Pontiac using the stock mounts that came with the car. Earlier '68-'69 blocks have only two bosses, while later '76-'77 Firebird-specific blocks have three bosses. These details may cause motor mount hassles with certain vehicle installations, but adapter mount kits are available from Indian Adventures and others to solve such problems. | 
For added rigidity, Moroso block fill is poured up to the bottom of the center freeze plugs. Though not essential, it fortifies the bases of the cylinder barrels against the elevated piston thrust loads brought by the 1/4-inch stroke increase. | 
The stock press-fit front-oil galley plugs occasionally pop out when high-volume oil pumps are used. To prevent this, the holes are tapped to receive 3/8-inch screw-in plugs with Teflon paste. A classic mistake is to thread the plugs in so they are flush with, or below the block face. If you do this, you'll obstruct the critical oil feeds that run to the main bearings. The trick is to thread the plugs until two full threads are showing (as shown) but go no further. Don't sweat about cam sprocket interference, it clears. |
The lifter valley oil drain hole is enlarged, and its bottom is ground down to the same level as the valley floor. This eliminates the factory lip and speeds oil return to the pan. | 
The two central oil drain back holes in the lifter valley are also enlarged. All rough edges around the lifter bosses are ground smooth and fully de-burred. | 
At the rear of the block, the internal oil galley plug on the passenger side is drilled to a 0.036-diameter hole that directs a constant stream of oil toward the distributor drive gear. It helps offset the added drive load caused by the high volume oil pump. |