Classic Inlines spent a couple days testing various carbs on our new aluminum head. The following data is the result of fourteen dyno runs made while we were there. For our first pull we used an Autolite 1100 carb with annular discharge nozzles, on a stock 200ci engine. This was done for no particular reason, other than to gain a perspective of the power made from a stock 200ci. The rest of the numbers are the results of the dyno test performed on Mike Raley's 66 mustang, using his current Holley 500-2V, and several Autolite carbs. It should be noted that the Autolite carbs, were pulled off the shelf. They were not custom built or tuned in anyway, to suit this particular engine. However we did re-jet them during testing, so we could obtain the best fuel/air ratio possible.

Engine Build: stock 200ci short block with ARP rod bolts, Classic Inlines new aluminum head with 184/150 valves, 264-110 cam, 1.6 ratio rockers, dual-out headers, and our DUI ignition system. The DUI dizzy is set up with 24 degrees of mechanical advance @ 3000rpm, and timing was set using a vacuum gage, at 16 psi. While were not sure what the initial timing was set at (no one had a timing light), Mike is trying to borrow one so we can find out, thus allowing us to calculate the total timing.

In summary the Autolite carbs worked quite well, in fact better than we expected. We were extremely please to achieve 225 plus rear wheel horsepower from this engine combo, which none of us thought was possible. We believe there were two reason for this. First and foremost, Autolite carbs are an annular discharge design, which was patented by Ford many years ago. This technique of metering/distributing/mixing fuel into the air stream vaporizes the fuel more completely, which improves combustion and performance.

It was also evident that the new aluminum head and intake manifold, prefer a specific size of venturi, at least for this set-up. The two carbs that made the most power, a 2V and a 4V, had venturi's which were 1.00 and 1.02 inches respectfully. When we tried a smaller venturi (0.98) we lost power, which we assumed was due to lack of cfm. When we tried a larger venturi (1.08), expecting a gain from the increase in cfm, we were surprised when we again lost power. Therefore we came to the conclusion that the size of venturi is extremely important for achieving the best intake velocity, and that the venturi size will vary depending on the cfm requirements of a specific build. This also verified that the intake velocity is directly relational to the power produced.

While the 240cfm-2V carb made the most power of the two barrel carbs, the 480cfm-4V produced a bit more. Therefore it is also safe to assume, while the 240cfm worked well, this particular build required more cfm than was available from the 240cfm-2V. This was provided with the vacuum secondaries on the 480cfm-4V, which resulted in the largest gains and the best power. We are not implying that this is the best carb available for a small six with an aluminum head, only that the 4V carb made the most power of the carbs we tested that day. It is reasonable to assume that a 390, 480, or 600cfm Holley 4V carb may have work just as well, however they were not available for testing that day. That being said, two similar builds using Holley carbs, are also making around 160-170hp, which is right where Mike was prior to dyno testing the Autolite 2V and 4V carbs.

Sid and Joseph, re-jet the Autolite 480-4V carb.

Gene, Collin, and MikeR (left to right) waiting to make the next dyno pull.

The results, graphs, and data sheets are posted below.

Holley 500cfm-2V (ported vac)


Holley 500cfm-2V (manifold vac)


Autolite 240cfm-2V with 48 jets

Autolite 480cfm-4V with 43/60 jets

With: Holley 500cfm-2V (ported vac)


With: Holley 500cfm-2V (manifold vac)


Autolite 240cfm-2V with 48 jets


Autolite 480cfm-4V with 43/60 jets