I have a 305 that I want to slightly "beef up" and I was wondering, will the internal "meshing" hold if I put a DOHC kit and twin turbos on it? Or should I just get a 350 or 400?? Thanks.

Cam, heads, intake, exhaust would be a "slight" beef-up.

DOHC & twin turbos - that's major. Don't plan on the stock block/heads/cam handling that.

"Don't plan on the stock block/heads/cam handling that."

If I'm putting a dual overhead cam kit on it, there won't be stock heads or cam....... I just want to know if the 305 block will handle it. Besides, is there even such a thing as an aftermarket or performance block?? I'm only going to use the block. Everything else is performance parts......

if youre replacing all the stock stuff with aftermarket stuff youre ordering, might as well ditch the 5 liter block and get a 350 block.

True. Brain and fingers got out of sync.

No aftermarket 305 block of which I'm aware. You could make a 5.0 liter small block with an aftermarket 4" bore block and 3" stroke crank.

With all the money you'll be dumping in this, it doesn't make any sense to use factory anything. Certainly doesn't make sense to build it on a 305 block.

Well i think your on the right track trying to formulate a plan so lets discuss that for a min. What are your goals for this car in terms of performance, streetability, legality, economy or anything that really matters to you in terms of what your want from the car. Also note when a i say performance i mean more is this going to be a street car a strip car if so what kind of 1/4, 1/8 mile, circle track or whatever kind of race you want to run what times are you expecting? From there we can figure out about how much power it will take to get you there and what kind of motor youll need to get there. Starting a build with numbers in mind with no understanding of what it actually means in terms of performance and driveability is a project doomed to failure. Also note where your want the power to be. Are you looking for a car that can burn rubber a mile long or a car that will scream away at 200 mph. I guess im asking what RPMs do you expect the car to be running at most of the time. Clearly if this is a street car wouldnt make much sence to try and build a powerband in the 3k-7k range would it. Now if you have questions as to what charateristics tend to go along with a certant type of motor (a screamer, torque monster street strip duty ect) chances are someone here owns one like it so we can fill you in on all the pros and cons of the build. Finally but probably most importantly theres also the budget to concider. So once you outline what you want we can start discussing the fun stuff displacements hp torque powerbands and equipment ect.

Rolling thunder, thanks for bringing that up. I'm pretty much thinking outside the box and wanting to think up and have something that nobody else has and I want it cool. I wanted to use the 305 because that's what I have. I like the looks of the crossfire intake. I know it didn't make much power, but it still is um... "unique". My thoughts of this is the crossfire intake with aluminum DOHC heads, twin turbos, electric water pump, MSD electrical, etc... But thinking about it more and more, I may just go to a 400 small block or an aftermarket block and if I do that, then I'd like to try and get and aluminum block if I do. I'd like to use a T-6 trans with the engine set up. I wanted to go with a supercharger but can't find one for that crossfire to save my life. I was possibly thinking of getting a ford 9 inch cut down for the differential.

The driveline is going into a 1982 camaro Z28 crossfire. I have some real nice color schemes and interior designs. I am going to have a sunroof installed since it's a solid top and I have never seen a camaro with a sunroof so it will be unique.

I know how to work on stock engines but not knowing much about turbos, boost, and exact specs like what valve lift/duration I would want/need for the DOHC heads so any and all help will be greatly appreciated.

Thanks.

What DOHC heads did you have in mind? Will a standard SBC intake even fit them?

this project can be done...but not for what it is worth.... you are looking at tens of thousands of dollars in parts... and you are all over the place... turbo this supercharger that... CFI will not fit on any DOHC head.. not to mention there arent any heads being made at this time only 6 engines were made by moser in the 70's....

try a UNIQUE Small block they will be cheaper and if you pick your own parts no one else will have a engine exactly like yours... and for much less money!!

Well alright hey do actually make 32 valve heads for the SBC but there expecnive. Check it out.

http://www.araoengineering.com/Chevy/chevysmb.htm

However youll start to run into the problem that the heads will probably flow better than the intake meaning youll have a mix match of parts. I mean how much would it suck as unique as it is if a twin turbo 32 valve 400 only put out 300 hp. Now if you like that style intake you could use one thats very similar that would perform better. Something like the cross ram use on some 1969 camaro z28s. Now as you can see the 32 valve SBC has some logistic issues but if your determined to have a 32 valve v8 why not look into the cadilac north start v8? Youde have to abandon the cross fire but they make make something similar for the northstar. For an aluminum 400 i think youve got a good idea useing aluminum very light great performance and uncommon in old cars but the SBC 400s kinda sucked. 1 in 10 blew out into the water jacket with cast iron blocks. Aluminum would be almost a guarented failure at some point. Ide say a better route would be trying to work with an LS series motor to get your 400 ci+ aluminum motor. However that means the cross fire intake will have to be abandoned again. You could run a classic aluminum SBC and bore and stroke it to 383. With an aftermarket block you may even be able to go further. Now any kinda forced induction set up will get attention and although you might have trouble finding a set up for your cross fire it can be done. You just need to look at a twin turbo single turbo STS centrifugal extera there are tons of options. Now keep in mind alot of this stuff will cost big bucks. Can be done and be absolutly amazing in terms of performance and image but a solid plan needs to be layed out and the funds collected befor the projects begins otherwise more than likely it will be another project that never gets finished.

My vote for "uniuqe", but still feasable, would be an ls engine. It has been done before, but there are not a lot of them running around, and you can get very good performance per dollar going this route.

Rolling Thunder, those aren't OHC heads like he is looking for. Those use stock cam location. But they would be very 'unique'...

So, OP, have you located the parts you'd need, such as the parts to convert a SBC to OHC's? And will you realistically have the money for this? It's going to cost a LOT.

Also, I think some thirdgens did come with sunroofs. I saw an '84 with a sunroof, but I have no way to verify if it was original or not.

So, I was thinking, if nobody's manufacturing DOHC kits for any sbc, then why couldn't I just put a Ford 302 with the DOHC stuff in the camaro?? I know I'm going to have to swap out the engine mounts for some customs a who new wiring harness but why not?? That's be extremely unique IMO. I've heard of people putting GM drive lines in Ford but not visa versa.

Any thoughts??

Because that would be wrong!
Seriously though, I don't think they ever made DOHC 302s.
If you mean the ford 4.6L or 5.4L, those things are huge, and would probably require a lot of work to put in a third gen.