I have a 1961 Chevy Biscayne 2dr. with a 350 horse 348, which means it has 3781147 heads, and tri power.
I want to put an Edelbrock 2x4 set on it. Are the ports on these heads considered small port or large port?
Offy makes a small port 2x4 manifold also, in standard and tall versions. I have no idea which one might work the best, I bought my Offy before the Eddys came out and felt like it needed work inside. Others may chime in on this, hopefully.
I believe the Edelbrock is better being a newer more modern design,but the Offy is decent.I doubt that,given that tiny "old tech" cam,that there's much difference between the two
I also have a 2X 4 Offy manifold on a 61-348 small head. I like how mine starts and drives even with the cast iron cased powerglide. It takes quite a bit of tuning to get it that way but the old eldebrock tuning guide worked great. I believe my final setup was their minus 2. No chokes either! Twin 500 cfm carbs but I had to use low profile manifold and thin phenolic spacers due to heat and vapor lock
Robert
I took a stock 3x2 off my 380 and put the Offy 2x4 tall one on with stock 409 carbs and my 1/4 mile times were identical. Then I added 1" spacers and it still ran the same...
My cousin were brain storming about this other 4011 block That I have.We're thinking about making our own sheet metal intake for fuel injection for the small port heads since I already have a 409 crank,and a very nice set of 817's.
The Offy will run better than the Eddy with a 3:70 or better gear. 360 design likes RPM. For the street, Eddy is probably the way to go. I run a 4:56 with my 2" spacer, tall Offy.