C2 :Fuelie 360 hp vs 365 hp carburator

[Bernard B.]

Which is the fatest on the street ?

The fuelie 360hp or the carburator 365 hp C2

Thanks

bernard

[Mike M.]

Re: C2 :Fuelie 360 hp vs 365 hp carburator

the 360 hp, a 63 fi, probably wouldn't out run an identically optioned 64-65 365 sbc. the heads of the 365 were 2.02 exhaust while the 360 valves were 1.94. the 375 rochester on the 360 was capable of 580 cfm while the holley on the 365 exceede 580cfm. mike

[Duke W.]

Re: C2 :Fuelie 360 hp vs 365 hp carburator

As built by Flint, the less than 3 percent higher power rating of the FI system in '64 and '65 is probably about right. Both are over rated by at least 10 percent (as are all 327 gross ratings from that era), and both are exceedingly weak on low end torque - to the point where they are basically poor high performance road engines, but the 365 HP probably has a slight low end torque advantage due to the dual plane manifold architecture.

The problem with both is head flow. No amount of cam or better manifold architecture will make up for the miserly flow of the heads as machined by Flint.

Now when you massage the heads the next limiting factor is the manifold architecture, and the FI is much more efficient in the upper rev range due to its large, straight, high flow efficiency runners and single plenun architecture. With a racing exhaust system a "blueprint stock" 375 HP FI engine can make on the order of 450 gross HP.

In street trim, it really comes down to the heads. Whichever has the best massaged heads - 365 or 375 FI will probably make the most power, but both will be within a few percent.

Replace the 30-30 cam in either with the LT-1 cam and you get about the same top end power and a lot more useable low end torque.

The Duntov cam in the 360 HP FI engine makes a lot more low end torque than either the 365 or 375 HP engines, with either Flint machined or OE heads, but for equal head flow the Duntov won't make as much top end power. That's the beauty of the LT-1 cam - almost as much low end torque as the Duntov and as much top end power as the 30-30.

Valve size isn't a big deal. I've seen a set of well massaged 1.94/1.50" valve heads outflow a set of so-so massaged 2.02/1.60" heads. Top end power is all about head flow. When you have good flowing heads you don't need a huge cam to get top end power that will simultaneously kill the low end torque.

Road engine performance is all about torque bandwidth. If an engine doesn't make at least 80 percent of peak at 2000, it's going to feel soggy in normal driving. Top end power is all about head flow, so you massage the heads for top end power, cam it for decent low end torque, and you get an engine that pulls from 1000 revs in top gear and makes useable power to 7000+.

So with any of these engines the way to go is massage the heads and install the LT-1 cam, and I don't recommend increasing the 1.94/1.50" valves to 2.02/1.60". The smaller set had a lot less tendency to develop a crack between the valve seats. Of course, if the heads already have the larger valves, it's not easy to go back to the smaller size.

It's all in the details!

Duke

[John D.]

Re: C2 :Fuelie 360 hp vs 365 hp carburator

"It's all in the details". A TI 350 HP car back in 1965 used to blow the doors off a 65 375HP car with a points distributor.
The TI car could rev much higher than the points distributor. But when my friend Tim Grabiak put a small piece of rubber behind (?) the points the 65 FI car blew past the 350 HP car. Road racing on the Lincoln Highway past a Bob's Big Boy at well over 120. Whew!!!! Wasn't me though. JD