Unusual 305

[Steeevooo]

How ya guys doing...I just started tearing my 1980 camaro berlinetta apart about a year ago, I knew it had a 305 in it the car only has 60000 miles on and I was going to proceed to make it a touring but do to the excessive rust because it sat in a pair tree field under a pair tree for 8 years (go figure) I decided to scrap the body and pull the motor out. I pulled to motor to find that the 305 has a 4 bolt main and I took it to an engine shop close to me to see if the block was any good and the guy said he has only seen maybe 3 of these in his lifetime and wanted to do a metal test on the block which came back about a week ago and the block has a high nickel content in it and he told me the block could handle a substantial amount of horse power. I still very much want to make a pro touring car but I figured id get the heart of the project finished off first and then find a rolloing chassis later on. I really want to make this motor a twin turbo set up just because Ive never actually seen a twin turbo 305...im not looking for a ridiculous amount of horse power id be happy with pulling at most 600 horse out of the block...can it be done? I just got a nice settlement from a car accident and want to build me something different...can it be done?

[ill steez]

thats pretty cool! if i were you i'd build a pro-touring/trans-am style camaro and just build the 305 up n/a. that would make for a pretty cool car.

[Restomod]

Did you measure the bore to be 100% sure??

[WS6]

I can't believe this until you give me a bore measurement, sorry. If this is truly a 305 awesome. I just can't believe it yet.

[Steeevooo]

I didnt measure the bore but the guy at the machine shop said it was deff a 305 ill get the measurements for ya though I also have the orginal blueprint on the motor I found in the car when i was tearing it apart ill see if I can get a pic of it on here...but in other words shud I just leave the block alone and buy like a new forged block from jegs or something and turbo that instead of going all out on this?

[Bill Howell]

.... I also have the orginal blueprint on the motor I found in the car when i was tearing it apart ill see if I can get a pic of it on here...

I would love to see that. Not sure what you are talking about.

If you really have a 4 bolt main 305, I would put it up and save it. You can turbo anything but replacing that rare engine block will be hard to do.

[Norwoodx55]

shud I just leave the block alone and buy like a new forged block from jegs or something

Yes. Let us know how that works out.

[MarkM66]

Interesting.

460778.....305...78-79...2 or 4, some Canadian assembled heavy duty truck blocks have 4-bolt main caps

[SPECWARSQUID]

Sounds a little wierd to me, but who knows.

There are rumors about "Factory" Canadian produced 305 blocks for certain truck applications. But no one seems to be able to produce any casting numbers. It's 2009 and I would think that actual evidence of one of these engine would have surfaced by now. Yeah I guess there is always a chance, but I would think that some of the inherant confusion between 305 and 350 casting numbers, mixed with bench racing might have been the origin of these rumors. All GM information with regards to the 305 indicates all these blocks were produced as 2 bolt and 2 bolt mains only. The one out in my garage on the engine stand is no exception.

Hey Steve if you are fortunate to have one of these engines, crack it open and lets measure some bore diameters and get some pictures taken of some #s.


____________
Semper Fortis

[MarkM66]

Yes. Let us know how that works out.

[cjrolke]

i have a buddy who has a 78 malibu that the original 305 was a 4 bolt main

machine shop never seen anything like it before

[WS6]

In terms of building a 305, someone will need to correct me if I am wrong but I believe the issues with why a 305 doesn't have more power potential has nothing to do with the cu in but everything to do with how they made the size. Meaning the bore and stroke were just a bad combination where as with say the 302 the bore and stroke were a good combination.

If you really want to build a 305, go get a 2 bolt one for cheap as they are basically given away and build it. You can four bolt it or stud it with steel caps. Either way will be strong enough for turbos and high revs

[slowcamaro]

2 bolt or 4 bolt, its not a wise engine to build. Sell the block to someone restrained with cubic inch limitations or classes mandating a 305 in particular.

The reason not to build a 305 has nothing to do with strength and everything to do with flow. The bore is too small to run decent heads.

I am not saying you can't make a 305 make power, If you throw enough money at anything you can make power. But you are better off starting with a 350. Dollar for dollar you WILL make more power.

[wendell]

High nickle boat anchor.

[silver69camaro]

A 305 is a 305.

[Steve Chryssos]

The reason not to build a 305 has nothing to do with strength and everything to do with flow. The bore is too small to run decent heads....

Yup. They have small 3.736" or 3.875" bores. More importantly, the small bores result in narrow valve centerlines in the heads. There is simply not enough room between the valves (because of the valve centerline) or around the valves (because of the bores) to allow for sufficient valve diameter. Cam, intake/exhaust runner volume, port size, and compression all must be matched to the point of maximum restriction. In this case, it's the valve head diameter.

All this makes a 2 HP per cube formula difficult to achieve.

[Randy67]

With the right head a 305 should make good power, not the 2 HP per cube level, but good power. Heck, the Ford 4.6L only has a 3.552" bore (3.543" stroke) and they run pretty good, even in the dismal 2V format (PI motor that is). Not ideal at all. Given a choice I would still spend the money on at least a 350 or 400 instead of the 305.

[novaderrik]

what's the bore on the mighty 5.7 liter LS1? i know it's somewhat less than 4", and they make good power and are more efficient compared to the older stuff with 4" bores.

[Steeevooo]

Just got the bore and stroke on the 305 its 3.74 x 3.48 is what he told me...it just seems wierd....i still have the body cuz i didnt have the heart to call the junkman yet the car has t-tops as well and they dont leak, and I checked to make sure the car was in fact a berlinetta and it is the 2nd digit in the VIN code is S making it a true berlinetta now i just have to find out about the wierd motor...maybe I should call GM corp? Any ideas?

[Steeevooo]

Im also stuck between a rock and a hard spot here. I went to the local junkyard about a week ago and they a beautiful 1980 trans am just siitting there, no rust,no rot,no motor...which isnt a big deal and since ive decided to put the 305 up in the raftors im probably gunna pick up a 350 B block from jegs with forged internals and go from there...i made a few phone calls to hellion about their mustang turbos and just poked around about the idea of throwing them in a pontiac and they told me they would be more than happy to make the tubing for me pending the motor size and turbos i went with...I also spotted what I think was a 70 maverick...ima ford guy at heart but I just love the way ponts and chevys look but I figured when was the last freaking time I saw a TT maverick? never lol...I just want some input and opinions on this one cuz both cars i think would be awsome