I'll start by saying I am religous about putting a 305 into my Camaro, I don't want to put a 350 into my Camaro. After that being said I have stumbled across the idea of a LT based 305. I want to take a LT 262 and swap out the rotating assembly with a 350, not only getting a 305 in the process, but also a 302. Anyway my question is are all of the parts on the LT engines interchangeable with eachother like the first generation engines? Because I really want to put a carb on it and I found a intake for a LT 350 that I would like to use on the LT 305, if I build it.

 

First let me start of by saying that you are going to catch major hell for this idea. Second, the only thing that you can swap out from the bottom end is the crank it self. The pistons in the 4.3 LT engines are the same as the ones in the regular 305. So in essence all you'll have it a 5.0 LT1 based engine. If you were to do this I recommend keeping it fuel injected, getting a set of aluminum LT heads and just doing a mild port job just to clean up the castings and port matching the intake to the heads. A ZZ4 cam would work great for this set up being a mild but peppy runner. no less than a 2800 to 3200 in an auto. I see that you have an 82 Camaro so you're going to need either a SD TPI harness and computer so you can run a stock distributor or you'll need to find the stock computer from a 4.3 LT caprice with the harness to match.

 

No advantage in using gen ii motors if you are just gonna carb it.

Keep it simple and just get a 305 sbc from one of these 87-92 thirdgens so you have the roller cams

 

Can't the LT engines take more abusive and handle more abuse than a first gen engines?

 

Not really. Reverse cooling helps alittle but its not a deal maker over a sbc properly done. You can stick a lt1 intake on a 305 if you want, just need to mod it to fit

 

You have already failed because:

350s have 4.0 bore
305 3.736
LT262 3.670

Rotating assembly includes the pistons, and they will not interchange.350 heads will not work on the smaller bore engines.


305s, 307s, & LT 262s are simply not performance engines. They were solutions to the 70s energy crisis.
The LT 262 V8 was only made for 1 year. 1975-1976 what does that tell you? They are garbage.


That being said if you are somehow fascinated by the "305" then you can easily make one using a 350 block and crank from a 283 and make a real 302, but unless that 302 is a road race car it will be a dog on street because you will never be in the power band the high revving 302 engine was designed for because it is a track engine not a street engine.


Find a new religion because your current one is not working well for you.

 

If you are going to try to diss something know what you are talking about. The 307 was made prior to the 1970s, the LT 262 was made in the 1990s and has a 3.736 inch bore and 3 inch stroke, you are talking about the first generation 262, not the LT based 262. The rotating assembly is the pistons, crank and rods. I was talking about the crank and rods, the pistons obviously wouldn't fit. If we are talking about first generation engines 350 heads will go on a 305, but heads with 2.02 valves will have shrouding issues. Also the valve train is what mainly made the DZ302s screamers, so if I were to custom make one it wouldn't necessarily only be a track car.

 

LOL so what, it's still a small bore V8

Building a SBC ( be it a gen 1, LT, or LS )with less than a 4.00 bore is a waste of time & money.

because no matter how much you try an engine with 3.736 bore will never outperform and equally prepared one with a 4.000 bore.

Even your beloved 302 has a 4.00 bore.

 

It is not a waste of money, if that is what you want to do. Not everyone wants or aims for the same thing. I want to build a performance 305, because my Camaro came with a 305 and I think it would be cool to tell people it still has a 305. You can easily build a 305 to over 300HP, so they aren't a bad performance engine.

 

I'd be able to use the connecting rods too right? And I would have to get all the accessories too?

 

I BELIEVE you can IIRC. Yes you would have to get LT1 accessories as your stock stuff won't bolt up. You can get a alt relocation bracket from ebay that drops the alt lower on the passenger side if you're not going to run AC (I'm doing it for BOTH of my LT1 builds). I believe that there is a bracket out there for the PS made so you an still run the stock setup I'm not terribly sure. I know I'll probably make one from scratch for my 91.

 

HP = TQ * RPM / 5252

So you can do the same with a 350 AND for less money.

not too mention because it WILL make more torque in the same RPM band, you make more USEABLE power for street driving.


I have a 421 sbc I tell people it's a 350, 355, 383, 406, all the time. Never a 305 because the car simply looks too fast to pull that off,, BUT.. from the outside all SBCs look the same... it's what's inside that matters.

Do your homework, you are not going to reinvent the laws of physics and mechanics. you can aim anywhere you want but if you aim low with a 305 build All you are going to have is a lighter wallet and a bruised ego when an equally built 5.0 mustang (also with a 4.0 bore, go figure) makes that 305 look like the turds they are.

A big heavy third gen simply needs the extra torque to move it so make as much as you can. this is why the 4.0 bore is better..

good luck

waveman:

 

Truthfully I have to agree with frmula88 on this one. I myself was hell bent on building a hopped up 305 back in the day. I had a VERY STOUT runner. the car was easily a bottom 13 second car when it was done. Looking back I really wish I hadn't have wasted my time. I got bored with that set up fairly quick, luckily I didn't have a lot invested monetarily in it, just a truck load of time. If you're going through the trouble of swapping in a LT based engine just start with a 5.7 LT1 instead. I promise you you'll be happier that you did.

 

Just wanted to point out for the less technically-minded (Im sure you're aware)... The 4 inch bore and 3.25 stroke (302) doesnt make for a bad street engine by itself. Plenty of factory stock Ford v8 cars had 4 inch bores and 3.25 inch strokes and they made decent power around town. Dad had a truck with a 4.00/3.25 v8 in it, and it made a healthy 185hp and 275 lb/ft of torque. Bore/stroke ratio doesnt matter beyond the bottom end's ability to stay in one piece at high RPMs, and even then it's more useful (as Chevy AND Ford used it) when you have a displacement-limited racing series simply because you get more power from increasing the bore than you do increasing the stroke. This is why staying with 305's is silly, because there is more power to be had in increasing the bore than the stroke. The powerband is determined by the cam and head characteristics relative to the displacement, not bore and stroke within normal ranges.



For the record, it's cool when a car has a 305 when it's either 1. Completely stock or 2. Insanely fast while appearing completely stock. But no matter how fast your 305 is, there's a guy with a 305 that's faster, and a guy with a 283 that's faster, and a guy with a 383 that's even faster. Just doesn't matter. If you want to do something silly with a 305 that still makes sense, turbo it. Then you blow it up and replace it with another free 305 some guy is tossing out because no one cares about 305's. For the average high mileage, moderately modified thirdgen, saying "it has a 305" doesn't mean much. Nice roller cam, aluminum heads, good intake setup, etc. That's thousands of dollars to do properly, at least $1500ish to do that well. Why do you want to spend $1500 on just cams and heads and intakes and make LESS power for your money? I mean you're going to upgrade it with fancy parts anyway, right? You're talking about building a 305 in a new block. That's like putting a Dodge engine in it and painting a bowtie on the valvecovers. It's not in any way, shape, or form the factory 305 anymore. It's just a 350 that didn't live up to its potential, since there's no exterior difference. What usually happens is you have a quick 305 and people just think you have a slow 350.

Have you ever heard ANYONE regret gonig to a 350+? Even the guys who get the crappy smogtastic 150hp 70s 350's have no regrets because I've never seen ANYONE say "Man I really wish I had kept my 305!" There are a LOT of times I've seen guys with crappy Goodwrench 350's or worse and they're plenty happy with it even though an LB9 would hand it it's lunch.

 

My Camaro is a 1982 Z28, so it is around 3,000 pounds which is significantly lighter than an IROC.

Also I know that a larger displacement engine would outperform a 305, if built to the same degree. I just like the idea of making a suped up 305. I really want to build a turbo charged one and that is why I am asking about making a LT 305, because from my understanding a LT engine can handle more horsepower than a first generation without blowing up.

 

Oh and before I get I also want to make a LT 302 in the process of making the LT 305, because I would have a 3 inch stroke crank and rods laying around anyway, so might as well use them.

 

Your understanding has no correlation with reality. Later model sbc's are arguably better than early ones, but it's definitely a give and take. But you're not going to see any real difference in strength or durability in factory parts going from, for example, a 1996 LT1 or a 1996 Vortec 350 or a 1992 L98. I dont really understand why it matters at all since you're going to be replacing the crankshaft and the pistons anyway, and there are many far better connecting rods out there than what GM provides. You're talking about the amount of strength of a factory rod with factory rod bolts being your justification for going to a Gen II smallblock that you're going to completely rebuild the shortblock on.

The LT1 engines MADE more power, and they ran at slightly higher compression while being reverse-cooled which has a slight benefit, but not much. GM didn't stick with the reverse cooling idea for Gen III+ engines after all.

The fact that a 305 or 302 or whatever it is you're actually going to make out of an LT1 (a 305 is not a 302 and a 302 is not a 305 so I dont really understand) will drastically lower your compression ratio plus the fact that most LT1's have aluminum heads would be beneficial if you're going to build a turbo system. But that begs the question... if you're going to seek out special 302 (or 305?) pistons, you can dictate the compression ratio to be nearly whatever you want, so it doesnt even matter that the LT1 can handle a little more compression.

IF you're going to turbo something, definitely dont turbo some pet project like this, because it's going to cost you a ton of money to build this (a straight rebuild of the LT1 is much cheaper) and when you blow it up it will all go to poop. Learning to turbo is not easy and there are many mistakes to be made through the learning curve. Not to dissaude you form learning it, but dont do it on an expensive unicorn motor that is emotionally special to you.

 

You make a valid point. I should probably experiment with a turbo on a cheaper engine while learning and wait to build my fantasy once I have more experience with turbos. I am more worried about the block than the rotating assembly, I have heard the first gen 305 blocks are only good to about 500HP, before the cylinder walls crack.

 

Um factory blocks are generally good to the 500hp mark. They will survive higher than that, but it depends on the block and how long you want it to last. Many times engines above that power level will fail via the typical failure modes and often they are actually caused by the block flexing in use enough to damage bearings, etc. But it's hard to empirically trace spun bearings and thrown rods to blocks that are shifting around so it's not something you hear about a lot. I know 1gary has done the tests on a 400 block used in competition situations and seen compression tests vary wildly from one day to the next because of the block moving around. But a 400 is a unique situation.

 

So the smart thing to do, if I want to build a 305, is just to do it with a first generation block? Because there are no significant advantages with a LT engine?

 

Depends, the LT engine IS a roller block. Gen I 1pc RMS bottom end parts will work in it. The question is whether or not you like the LT1 fuel injection system, because other than a potential reliability issue in the optispark, it's a very good system, especially for high RPMs. The LT1 EFI system is pretty much the big benefit of an LT1 engine. The reverse flow cooling is a bonus but doesnt amount for any real advantage over a Gen I. You will need to convert a few things over to fit it into our cars. Otherwise you can get a miniram which is basically an LT1 intake but with a few issues of its own. It's also very expensive.

If you want to make the necessary sacrifices monetarily and practically to build a high RPM screamer, the LT1 intake is one of the better options for that. It wont make for a very fun street car, if you're raelly pushing those limits, though.

If you want a streetcar, build a 302/305 around something like the 260xfi. If you want a high RPM screamer, you'll want a solid roller cam. At least 230/230 duration, more if you are willing to deal with it. The RPMs it will hit will require some pretty high end ($$$) parts throughout the motor for it to live.

 

No, smart thing to do if you plan to make 500+ HP is use an aftermarket block. Your block will be a 350, because the aftermarket does not make 305 blocks

Unless you have a complete machine shop at home you will be hiring a builder / machinist to prepare the engine for assembly.



Seems to me you have a case of champagne dreams and a Gatorade budget.

 

There's a limit to what you can do with old-school GM passenger-car parts, and the breaking point is relatively low when it comes to the Gen I small-block Chevy cylinder block. Sure, you can bore the block to within an inch of its life and fill the water passages with concrete before stuffing a 4.00-inch stroker crank into it and make decent power for a while. The fun won't last long, though, when the block cracks, leaks water, or flexes enough to pinch the main bearings or lose the head-gasket seal. To find the beef of the stock 350 and the aftermarket alternatives, we had Pfaff Engines sonic-test six different blocks with 350-style main journals (some are available with 400 main journals) and standard deck heights to see how far they could be bored and how thick the decks were. We also put them on the scale and called every manufacturer to find out how much work it is to drop a big arm into each one. The results were surprising, but we are savvy small-block Chevy shoppers now.

Read more: http://www.hotrod.com/techarticles/e...#ixzz2figXPg1Q

 

Stock blocks can handle about 360 HP.

If you plan to go with a turbo & make 500 HP your best budget solution is a Dart SHP block which is rated to 600 HP.

for a little bit more a Motown II or Dart Little M will get you into 1000 HP

The other advantage is the aftermarket blocks do not have the engineering "flaws" found in the OEM block, as such they are simply a much better foundation for a hi-performance build.


People will spend $$$ on heads, cam, pistons, etc but cheap out on the block, when in fact the block is the most important piece of the puzzle.

 

Ratings are just that....ratings. So many examples of people making big numbers on all kinds of blocks. Seen many 500-600 hp stock block builds including 400 blocks. Eventually they may fail but really depends what kind of abuse you dish out. If a block can last a season at circle track races making 400-600 hp at 6000-8000 rpm, doing 20-30 races a season for hrs on end, without failure, do you think a street car that sees 5-10 passes a year down strip will hurt it?
Dart shp rated at 600, i've been at 700-850 for past 3-4 yrs but not that much time spent on it. Dozen passes or so and countless street pulls. I know a few others making loads more power than me on shp's. 9.04 second nitrous street car to name one on this board.

I wouldnt be to concerned with sub 600 hp on stock blocks as long as they check out ok from machine shop. Avoid overbore as much as possible.

 

Alright I think that is all the questions I had. Thanks for the advice guys.

 

ahem, I will now point out something some people are overlooking.since you have 45 less cubes,you can use less gas. I built mine back, bone stock as a baseline. I get 20 MPG IN TOWN!! on the freeway its 26. not too bad ,I think ,for a v8 car.if you aren't interested in racing.but just want a economical and fun engine ,then by all means ,go for it.world products make the "torqer SR" heads that can be ported.cams are available too .300 horse power is not a unreasonable goal.granted I have a TPI car ,if you run a carb expect quite a bit less on the MPGs

 

There's a whole lot more to fuel economy than displacement. In the grand scheme of things with a performance build, fuel usage will be correlated to power output more than displacement. I wouldn't be surprised if a larger engine will get better gas mileage than a smaller engine at the same power level (assuming everything else is constant, which is relatively unlikely but for comparison's sake...).

 

That is actually true, if a smaller displacement egine has to run higher RPMs to accoplish the same power out put as an engine with higher displacement, the smaller displacement engine can end up drinking more gas, because it has to run a higher RPMs thus needing more gasoline to accoplish the same power output.