The Edelbrock Super Victor...
The Edelbrock Super Victor has proved a good companion to any of the performance iron heads we are dealing with here. Top that off with a well set-up 750 Holley or BG carb (750 Road Demon shown here), and you have an induction combination good for 500-plus hp without breaking the bank.
All of the heads we are discussing will work better if the quench clearance is nearer optimal. Getting it there usually involves machining some 0.020-0.030 off the top of the block. That's a $100 deal, minimum. The cheap way to avoid this cost and save money on head gaskets is to use a stamped steel gasket. Felpro's piece has a compressed thickness of 0.016-0.018 compared to the normal 0.038-0.040.
Although the "as cast" flow numbers of all these heads are good, there is still a lot of additional power potential locked up in the ports and chambers. Because the ports are inherently well designed on all these heads, we find that minor casting flaws can have a bigger influence on the final flow numbers than on heads with lesser ports. Spending just a few hours doing the minor work needed to "pocket port" these heads can pay some handsome dividends for those classes where the rules apply to "one inch down from the seats and one inch in from the manifold face." For instance, on the EQ heads, the flow on both the intake and exhaust showed increases starting at about 0.200 lift. At 0.250 the intake flow from pocket porting went up from 163 to 166 cfm. At 0.600 lift the flow rose from 259 cfm to 279. On the exhaust side, the numbers, at the same lift points, were 107 to 111 and 169 to 179.
At this point we have covered the long-block and it's time to consider what we will use for ignition and induction. There are a lot of options but to demonstrate the practicalities of budget power we will not use anything fancy (and otherwise costly). For ignition, it's hard to beat an HEI upgraded with a performance module from MSD or Performance Distributors. We have rescued HEI units from the wrecking yard, cleaned them up, and equipped them with a Performance Distributors module, and for less than $80 had a system good to over 7,500 rpm.
With the typical 200 cc intake ports that seem best suited to a 350 racer targeting 500 hp, the Edelbrock Super Victor repeatedly delivers the goods. Just for the record, EQ has a whole load of these with minor casting flaws for $130 a pop. For carburetion, let's go with what must be the most popular size of four-barrel-a 750. Looking at prices, we have seen a Barry Grant Road Demon go for as little as $300 and an equivalent Holley for only a little more, so power curves with a 750 carb is what we will be looking at here.
Iron Heads & Hydraulic Roller...
Iron Heads & Hydraulic Roller Cam Test
These curves demonstrate just how much potential for cheap power there is in a late-model block. The key factors toward producing high output cheaply are a good set of iron heads and the fact a late-model engine comes stock with a roller cam.
Any time cost cutting is a factor, chance-just like a roll of the dice-can be a positive or negative factor. The two example engines shown here are just such cases. The blue curves on the graph are for a 10.3:1 motor on EQ 180cc port heads and a single pattern Comp 288 Xtreme Energy hydraulic roller cam. The red curves are for pocket ported heads, a CR of 12.5:1 and a single pattern Comp Cams 293 Xtreme Energy hydraulic roller cam. For the blue-curve engine, our high mileage donor motor needed a re-bore and new pistons. Some KB hypereutectic pistons were very cost effective here, but this and a few other wear issues put the cost of this engine to just under $3,100.
The red-curve engine was a luckier deal. It was a low-mileage unit that had seen frequent and regular oil changes. It was in pristine condition internally to the extent that we reused all the rings and bearings for the rebuild. Block prep consisted only of a bore deglaze and a really good cleaning. When the pistons were stripped of the rings and cleaned to the bare metal, they came back "as new." This engine ran a total of $2,580 but a new Performance Distributors (good to 8,500 rpm) HEI unit was used. If we had rebuilt our old HEI with a Performance Distributors race module instead of opting for a whole new unit, over $100 would have been saved.
There is more power in the late-model, roller-cam block/iron-headed motor than you see here. I am sure with a fancier race-style pan, a more aggressive cam and a few other refinements, 525 hp is a reasonable expectation. But the cost is going to escalate. On the other hand, if rules are made that restrict the CR to, say, 10:1 (pump gas will work for this) and 0.500 valve lift, along with a 6,500 rpm rev limiter, power would be held in check at a nonetheless healthy 450-470 hp. At this level, most stock parts have a reasonable chance of surviving. Throw in a set of hard compound tires and just maybe we could cut the influence of big bucks by a big margin.