What car/trucks did they come on ?

 

They only came on trucks and burbs. Casting numbers are 062 and 906 and you can tell by one having a single half moon and the other having 3 pointed saw tooth on the end of the casting. They also have only 8 bolts holding the intake to the heads and no bolts in the middle.

 

So will they just bolt up to my 305 I know I will need a new intake ,valve covers,cam will I be able to use my oem manifolds with them till I can get my new headers put in the car

 

What you just described was the old hotrodder's 301 ci Chevy that was built with a 327 small journal and a 283 crank. They were fun engines that later became the basis for the DZ302 that made early Z28's so popular and fast!
I toyed with building my large journal 327 into a 302 by using the large journal 302 crankshaft from Eagle. But in the end I hated to rebuild a good running engine, and spend more money.

 

That is not correct. The whole casting on the 305 is different. It was designed in the 70's and at the time GM (or anyone in the US) did not know how to build an emission friendly high HP car. So when they designed the 305 they removed weight everywhere they could. I use to build race engines and even back in the 80's the 305's where dirt cheap. I cornered a GM engineer at the Pittsburg GM tech center and started to ask him about ways to use the 305 in racing. He told be flat out. The main webing in the casting itself is not strong enough. No matter what parts you put in it those parts will fail because of the flexing in the block. Now you don't have to take my word for it. Just look for a race team that uses these easy to find blocks. Infact just look for build theards of guys building motors and acually racing them. Then follow through and see how the thread ends.

I have seen it time and time again, people dumping money in a 305 only to end up with scrap metal. I think we have a few members here that have gone thru the process.

 

Not to mention, you can't bore out a 305 block (3.736" bore) over a quarter of an inch more to achieve a 4.030 bore. You have the same cylinder wall thickness restrictions as you would with a 350 block. So using a 305 block for that "high winding great breathing SBC" isn't even an issue, because you can't.

 

You would just use the 350/327 block with the 4 inch bore and the short stroke crank to make the 301. Back in the day when I started racing we used the early 283 blocks with the thick side walls and bored them out to 4 inches. It was very common to do that back in the early 60s. You already had the short stroke crank and you only need to bore the block. Could very well be done to this day if some one has the early 283 complete motor.

 

Its been posted many times before. Run the 305 till you can get your hands on a complete vortec motor and build that up the way you want. You have the 350 inches, set up for a roller cam, you have all the parts for the roller cam, spiders dog bones lifters cam reatainer and ever the roller cam if you can put a electric fuel pump someplace. (their is no lobe for a mechanical fuel pump on a stock vortec roller cam). You could use 1.6 rockers on the stock cam and it would help with the lift. Even with a good cam upgrade you could be looking at close to 400HP on these vortec motors. Or you could go on ebay and get a 383 stroker kit for the standard bore (377 inches with a standard bore) if you needed a crank because of a spun rod bearing.

 

I don't want a 383 they are nothing but trouble our airboat has one sure it has the power but that motor seems unreliable since we have had it 3head gasket changes 1set of heads and right now it has a rod knock I think the place we bought it from might have it a used motor in it the thing is only 3years old stays cover only runs prem fuel has less the 100hrs on it and also right now I'm trying to sell my camaro I'm wanting a corvette c4 or a sport bike

 

Your comparing apples and oranges, Marine application is completely different then a street motor. A 383 is designed for Hi torque low RPM application. I think you would be much better off lower displacement high reving motor like a 327/302. Cooling can also be a problem on boats.

The 400 SBC is the highest torque small block but it comes with a cooling weakness that can cause problems. For many race teams the 383 is engine of choice do to the fact it has the same stoke as the 400 but it does not have the cooling weakness. Remember the 383 was never put in any production car and most are assembled by local machine shops. When done right they are very dependable. In my head it is pretty funny that a 305 owner would call a 383 “nothing but trouble”. Kinda like a Chevette owner calling a Corvette a POS. I put together a budget 383 for a friend back in 1989 for his 1967 Impala. He has about 55K on it and it is still going strong. He now is dripping oil in his drive way. I told him the least we should do is reseal/gasket the whole motor. He said he is not in a hurry.

I don’t know how old you are but you really want to check out insurance rates of the Vett if you under 25. I too would love a C4