i decided to ditch the basket case 305 that was in my firebird, i traded it for a 79 350,

now i dont want to hear anything about putting the 305 heads on the block, because i already know you'll get better compression, but i traded the whole engine and im not looking to win races

first thing, is there anything i need to do to the body of the car? to have it run correctly that is, i dont think there should be but it doesnt hurt to be sure

2nd i still have the quadrajet from the other engine, would i have to find a 305 intake for it (which would also mean 305 heads right?) or is there a 350 intake that would work?

3rd down the line i would like to change it to a TBI like my camaro, i know i would have to get an electronic fuel pump, but what would i do about the manual one on the block itself? would i just get a plate to cover it? would it even be compatible with the block itself?

sorry if my questions arnt clear, ill try to explain better if needed

 

A small block carb intake is a small block carb intake. If it fits one sbc it will fit them all so any carb intake should work. As long as it fits under the hood, there shouldn't be any body modifications. All small blocks are the same size.

Can't help much with the fuel pumps though, all my cars are FI.

 

by body i kind of ment wiring, but i figured the small bock stuff was interchangeable, better than buying it being only 1/2 sure then it doesnt work

 

Do you have a throttle body already? You said you don't want to win races, so why not just throw in a mechanical fuel pump, hook it up to your current lines, and throw on a carb?

It'll be a little easier, and you won't be limited on future upgrades by it like you will TBI.

 

My apologies, wasn't sure what you meant by your question. If you are using an older block and a carb vs tbi then just use whatever hei distributor (came with the 79 motor?) and that should be about it. There's not really a lot of wiring on a carb'd motor.

 

There will be 2 things different between your '86 305 and the '79 350 as far as what bolts to the engine:

1) The dipstick will be on the driver side. That means the dip stick tube will try to occupy the same space as the factory exhaust manifold. You can try to bend it and get around the manifold, or you could get a flexible tube dipstick, or you could get headers.

2) The rear main seal of the 305 was the 1-piece type. The '79 rear main seal is of the 2-piece type. That means the flexplate will not be the same between the two. Get a flexplate for an '82-'85 f-body V8 and you'll be fine.

Now, converting to TBI is a slightly different story. First, the heads have a different bolt angle for the intake mount bolts for any TBI manifold you find. You'll have to modify the TBI manifold to fit the '79 heads. 2nd, you're better off finding a 350 TBI system to bolt onto it to minimize modifications (things like computer tuning). You'll need to make a lot of changes to the fuel system - pump, lines, hoses, etc. The mechanical pump on the engine will be out of the loop (yes, you just put a plate on the block to close the hole).

Oh, did anyone mention '79 350s had about the worst heads the factory ever foisted on an unsuspecting public?

 

I don't want to dissuade you from getting that 350, but if you're just looking to get the car back on the road, getting another 305 that's more similar to what you have will be the easiest. That 79 350 probably makes LESS horsepower than your stock 305, so you're going to wind up going through a lot of effort to get it to work, and wind up with a worse motor than what you had. You can probably get another 86+ 305 for a couple hundred bucks.

 

im not in a hurry to get it running

i think im gonna ditch the TBI idea, i still have my quadra jet so im gonna stick with tah untill i can get a better carb

the engine that i had in the firebird was not original to the car, it was an 84 lg4 and i didnt want to rebuild that entire engine, the PO was a dumbass and it seemed that the engine needed one of everything, so it having the same HP doesnt bother me

and as for the heads im going to be getting 305 heads

 

This is so true I would for sure ditch the TBI idea and stick with a carb. I love EFI, but sometimes I wish my cars had carbs. Around here it seems alot of guys run a 71 Vette 350 when they swap 350's into a 3rd gen and with some mods they run killer.

 

Yup; there, here, and everywhere else...

There's about 73.8 times as many "71 Vette 350s" in kids' cars nowadays than there were 71 Vettes. Kinda makes ya wonder what would possess an otherwise sensible human being to disassemble SO MANY unfortunate 71 Vettes and part the motors out on the open market for relatively speaking peanuts, doesn't it? I mean, REALLY, who would do that? Why? WHAT ARE THEY THINKING as they do it? At least it should, before you repeat that drivel and hide it as "advice"; because if you did, you'd realize that it's A LIE FEEDING A FANTASY WHILE RIPPING OFF THE GULLIBLE.

Just like there's a similar multiple of 69 Z28s on the roads today than what GM sold in 69.

ANY 350 can be made to "run killer". They're notoriously dumb; don't remember a damn thing about what sheet metal (or even fiberglass) they were last wrapped in. All they care is, THE PARTS they're built out of. You can take a 160 HP 350 2-bbl out of a phone company van, and turn it into a 650 HP monster; all you gotta do is bolt the right parts into & onto it.

 

The reason there are so many 71 vette motors is because that year had the terrible body rust issues...

 

Oh yeah, I forgot about those... that would explain it.

Kinda reminds me of sending the n00b to the parts store to pick up a Corvair water pump. Not that I would EVER consider such a thing; just sayin..

 

Like the quote from Don Yenko
"we built seven of those SS cars in '68 ; there are still nine in existence today"

And of course everyone knows that if you have a 4 bolt "010" block it has to be a 370 Hp Vette LT1 engine

 

No joke, I had a new guy gone for 4hrs all over town looking for a bucket of steam.. (all the other shops were in on it)
Also got him a week later. The whole town was out of sky hooks that day.....

 

also i forgot to state in the first post, its not an entirely complete 350 or put together, it is missing things, and the heads are off a different engine, they are cleaner and painted orange where as the block is factory blue

 

What's the casting #?

What machine work have they had?

That's about all that matters... color is pretty easy to change if you don't like it. They'll come back from the machine shop "natural" regardless.

And of course, putting together is , ..... just that. Not too much of a problem. Misssing things though, that depends on what it's missing.

 

the casting number is 3970010 i forget the id number but according to that is from a 79 f or b body

they havent had any machine work, the PO told me it could use some

as for color i was doing orange and chrome

and putting together inst the hard part lol just getting everything

 

That's THE SINGLE MOST COMMON CASTING NUMBER EVAH.

At a guess, I'd say about 40% of all 350s ever made used that casting. It was produced from 69 to somewhere close to 80. There are MILLIONS of em still in the world.

Every imaginable variant of 350 was built out of it. Which is no surprise, because THE BLOCK doesn't "have to" be different for any particular reason, to build different ENGINES out of.

I owned a 79 Z28 4-speed... it was a complete turd. Slower than a snail frozen to a log. Traded it in for my 83 L69 car. 180 HP if memory serves, compared to the 83 305's 190 HP. Pretty disgraceful. I also had a 78 Z28 (auto) at the same time, the L69 would outrun that one so bad it was like it was standing still. But as I already said, THE BLOCK is totally irrelevant to the power that THE ENGINE produces; you can take THE BLOCK out of a 74 Impala 4-dr 2-bbl and build a 700 HP Outlaw ENGINE out of it, or take a 71 Vette 350 BLOCK and stick rebuilder pistons and a 929 cam replica in it and put 882 or 624 heads on it, and turn it into a 160 HP 76 construction company truck ENGINE. The BLOCK doesn't control, or even influence, the power output of the ENGINE.

Post the head casting # and we'll be able to tell right away whether to throw em in the trash or spend money to freshen em up.

 

the heads are 3986339

 

EEEeeeeewwwwwww....

Doesn't get much worse than that. I don't think the motors with those made even as much as 160 HP. Prolly more around 145 - 150 HP on a 350, and 120 HP on a 307.

307/350 with 74cc chambers. 2-bbl heads. And here I was talking about 882 or 624 heads like they're bad; 882 and 624 were the "performance" heads in those years (came with the 4-bbl carbs), and they still SUCK so bad I've actually paid people to come haul piles of em off my property because they weren't even worth the effort of hauling em myself to get the scrap cast iron price, And here, 339 was the least common denominator, the lowliest of the low. I'm betting there were probably a bunch of those in my 1-800-GOT-JUNK piles back then, too. Almost had to have been.

First thing you need to start looking for, is better heads. You have NO HOPE WHATSOEVER of being able to compete with ANYTHING with what you've got. It truly is the worst of the worst.

Sorry to have to be so blunt, but... better for you to know NOW, up front, than to waste a bunch of time money and effort around them thinking you're going to be able to use them for something.

 

i wasnt going to use them in the first place...

 

Excellent!! Now all you have to do, is figure out what you WILL use.

 

yes i know ;p i was gonna research some 305 heads

 

Why 305 heads? (not saying they're necessarily "good" or "bad", just looking for your thought process)

 

just everywhere i go i hear "put 305 heads on it, you'll get better compression"

 

Not necessarily...

You'll get higher compression; whether that's better or not, is another matter entirely.

350 heads (although the really really low-perf ones like 339 may differ) mostly come with 1.94" intake valves and 1.5" exhausts. The really high-perf ones from the factory sometimes came with 2.02" intakes and/or 1.6" exhausts. The extreme lowest perf ones may have come with 1.72" or 1.84" intakes.

305 heads usually come with 1.84" intakes and 1.5" exhausts.

Not hard to see, by just jamming a pair of stock 305 heads on a 350, the intake side is suffocated. Now in some cases - specifically, where SOME OTHER limit to the flow is "The Bottleneck" - the restiction of the tiny valve might not matter so much, and the increase in compression from around 8:1 to nearer 8½:1 might be "better". This makes this approach only of value for really crappy stock smogger motors with restrictive intakes, choked exhaust systems, and inadequate cams. IOW, a backyard shadetree el-cheeeepo hack, and not universally applicable.

However when building an engine from scratch, that's probably not the way to go.

Another choice is, you could take a pr of 305 heads and install 1.94" intakes into them. Problem with that is, it leaves the edge of the valve RIGHT UP AGAINST the "vertical" wall of the chamber, as shown in the rectangle in the pic. It doesn't really matter how big the valve is, or how far it's opened by the cam, if all the incoming material has to sqeeeeeeeze between the valve and the casting. To fix this, you have to lay the chamber back around the intake, which increases the chamber volume; usually by the time you get enough material removed to get a good payoff on the valve size increase, the chamber is up to 61 - 62cc. Not near as much of a bump in compression. And also, in the process of all this, there is risk of thinning the castings so much they'll crack, removing the hardened metal from the seats, and various other fatal side effects. It's not risk-free.



Plus, you'll end up spending MORE doing this in most cases, than just buying a set of cores already so equipped; if you can't do all the port work yourself, then this is absolutely NOT the best way to go.

Best way to build a motor in general, is to use flat-top pistons, chosen to get their deck clearance (something usually overlooked by novice builders and even more so by novice "compression calculator" users) as close to zero as possible, then decking the block to MAKE IT zero; and then choose heads with chambers sized to give the desired compression. For a street 350, this combination would result in as small as 58cc chambers for aluminum heads, and 64 - 70cc chambers for iron heads.