Is anyone here using the GMPP small block 330 ho or zz4 in a 65 chevelle? I am interested if the oil pan fits and what headers are you using? And what is a mellonized gear for the distributor? My 305 sb is loosing oil preasure when it gets hot after a while, down to about 10-15 pounds from about 40 when cold. I've read that it is most likely bearings. I am going to try the rottella 30 wt oil 1st. May be that will help. How about the 350/290 set up? I could buy a new tranny at that price. I sure do like the 305 mpg though, Thanks

I am installing a Goodwrench 350/260hp in my '65 Chevelle. The oil pan is probably the same as the HO and zz4. There is plenty of clearance between the oil pan and the frame crossmember.

I am using Hooker Comp headers - bought used from someone on this site. They fit fine, but needed some dimpling to clear the manual transmission bellcrank/countershaft/z-bar.

I don't know about the distributor gear. I am using a stock points distributor. It fit fine.

That oil pressure indicates that the main and rod bearings are worn, but not necessarily that the engine is shot. It probably has a decent amount of life left in it, if that is your only problem. The engine is nice and loose - maybe a help with the MPG. Using a heavier weight oil will probably make the oil pressure go up, but won't really improve matters with the worn bearings.

the melonized dizzy gear is for use with the ROLLER CAM IN THAT CRATE ENGINE falure to use it and your warrenty goes bye bye and so does the cam dizzy gear...
an iron dizzy gear will kill the roller cams dizzt gear...
unless you want gear parts in your oil .. use the melonized gear

I have a ZZ4 that I am putting in my 65. I test fit it a couple months ago and no problems on the oil pan.
The headers are a little tricky though. The problem I ran into was I needed a short header that fit angle plugs as well as D-port heads. The only two I could find was Headman and Sanderson. The Headman quality was not very good and the left side hit the lower control arm bracket, so I sent them back. The Sanderson seem to fit well, very close to the steering shaft but I think it will be OK. The quality was much better.

I have a ZZ4 in my 65. Fits great. Used Dougs Headers with just a slight interference with the steering shaft (slight dent required for clearence). Demon crate carb (650cmf). Custom Magnaflow exhaust. Dyno'd around 300 hp at the wheels. Have about 5K miles. No problems. Coupled to a 700R4 trany.