Have you guys read this its a few years old


305 Chevy Engine Blocks - Engine Masters Magazine

 

Like all things its in the cylinder heads and cam choice of any build. The vortec heads are the real key and their cheap and plentyfull with the factory castings.

 

I know flow is an issue with the 305 but IMO the biggest problem with the 305 is the weak bottom end. That opinion comes for having under warranty 305’s that needed crank kits wait for me to finish installing a 305 crank kit. At the worst of it I did (3) 305 crank kits back to back in 1989 all on bone stock under warrant. In every case I can remember the issue was a stretched connecting rod that caused a damaged crank. I really think the engineers pushed the design limits with the 230 HP TPI. To put that in perspective I never did a crank kit in a L98 350. I did have installed new motors in a couple of vets but that was caused by overheating. Maybe the 305’s got better with age?

The only GM motor that had as much issues with the lower end was the early 2.8s. The 2.8 went through a series of upgrade that improved the issue. The 305 never did that I am aware of.

 

I just thought it was cool a 370hp 305

 

Oh it is cool, I just like to give guys heads up. If you do anything like this be prepaired to turn you motor into scrap metal. Back in the day motors built without regards to how strong the bottom end where called grenades. At the track we use to say lets go watch them pull the pin.

 

Why would the bottom end be different then the 350. Other then the bore everything is the same. If I was doing something called a 305 I would do a 4.030 bore with the stroke of a 283 and have a high winding great breathing SBC. I would use the later casting and then would use a good solid lifter cam and wind that thing up to the moon.

 

where would I go to get some vortec heads ?

 

New Chevy 5 7L Vortec Cylinder Head GM Casting 062 Free Shipping | eBay

 

you could also try summit

 

Or just ask around. There are some in the salvage yards or look on cragis list or you local paper.