Big Block Guys

[pats71]

I'm getting a headache from the guys over at moparts and figured I would come over here to ask this since they're getting way into details pertaining to race motors and not street driven.

Basically I was going to go with a spare 69' HP 383 and 4 speed to put in place of my numbers matching 383/4 speed. Problem is the guy that gave me the block gave me 10 main caps, and only getting #1, 3, and 5 while the rest are 440 caps. So I decided to build up the spare 78' 440 I had and even had a forged crank and pistons for it while I had nothing yet for the 383.

So my basic question is how are you guys running on pump gas? Based on the info, below should I have a reason to worry, or are the guys on moparts trying to build me a race motor?

The overall short block is using replacement 6 pack pistons, L2355F30 forged pistons, stock LY rods (not 6 pack rods), and a forged crank. The heads are going to be an open chamber style. I have to get another set from aero head because the 452's I had magnafluxed had small cracks around the valve seats. This engine is only going to see the street and is just meant as a replacement for now while I do a rebuild on the numbers 383, and put it aside for an all #'s matching restoration.

The guys on moparts seem to be trying to put the fear in me that if I don't achieve quench with a closed chamber piston and different pistons, then my motor is going to constantly detonate.

[racedodge]

that is the problem with those guys over there.. they only see "results" based upon a finite number of parameters.... in other words, they can't see the forest through the trees. They only believe in "ideal" engine combinations and do not understand why someone would build something based upon what they have on hand and not what they should buy (at incredible prices if need be) to obtain that 9 second car.

you will not have pre-detonation problems if you ensure that your timing is not too far advanced. With the 88cc head of the 452, you will find that your C/R will be around 9.9-10.1 to 1 (considering your 6 pack pistons are 10.5 to 1. Closed chambered heads generally increase the compression ratio of a engine about.4-.6 pts based upon the head (each has its own casting differences).

Based upon your cam, your timing and the carburetor (a/f ratio).. this will actually determine if you are to have detonation issues, not just your C/R.

If you are still worried about "ping", just put in a thicker head gasket and you will get closer to 9.6-9.8 to 1 and no worries on ping there at all!

[pats71]

I'm going to be running the EZ-EFI kit in place of a carb and I had to buy a set of 452's from aerohead. They come with 2.14/1.81 valves and are basically a bolt on deal.

I called Hughes Engines afterwards and they recommended their 2328 cam.

[racedodge]

as long as you run premium fuel and do not get too crazy on your advanced timing, I do not think you are going to have any issues.