Getting back at it, help please! - Impala Tech
Engine General Engine Discussion.

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  • 1 Post By japete92
  • 1 Post By 68WASAGOODYEAR
 
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post #1 of 7 (permalink) Old 02-11-2020, 01:25 PM Thread Starter
 
 
Join Date: Jun 2013
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Getting back at it, help please!

So after a long 5 years or so of a crazy life leading up to finally getting a divorce and starting to get my life back to where I want it to be, I want my baby back on the road!
So it has sat about 5 years or so, the last issue to my knowledge was the need of a new carburetor. Now that it has sat, I would appreciate some guidance in getting her back up and running. I have done a good bit of reading, so I know a bit about pulling the plugs, putting some marvel oil down the cylinders, and trying trying to dry crank the engine with the starter and a battery or similar process, changing the oil, fuel filter, antifreeze, taking out old gas. I just want to be sure I'm taking all the proper steps and in order they should be done. ***If there is a detailed post here already then I apologize and send me to it

Now pretty bone stock 305, so boring drive, so I keep thinking back and forth of bypassing the care of this engine and just dropping a new one in. Now if I go that route, I see the common suggestion is a 350 crate engine which I can see can be found just about anywhere. I'm excited to drive her again, so my question around this route is, should I get the 305 running and then drop a more powerful engine in later(I can drive her sooner) or just wait it out and chuck the 305 and put a bigger engine in, and if so, what do you suggest for an engine? ***I'm not looking for some crazy high performance drag racer, I just need some good get up and go when i want it, highways, fun, etc.

I appreciate any feedback and glad to come back to this community!
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post #2 of 7 (permalink) Old 02-11-2020, 02:37 PM
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Torque is what you feel in the seat of your pants. Torque is generated by displacement, especially if you are stroking the engine to obtain that displacement.

Your 305 has the same stroke as a 350. Bore is smaller than that found in a 283. The bores are so small that 2.02" intake valves will hit the block, so a 1.94" is as large as you can run (though it will still not breath well because half of the valve is shrouded by the cylinder wall). The 305 was designed to use the 350 crank as it is one less part to keep in inventory and the engine needed a long stroke to compensate for the small bore to move the mass of a pick-up.

If you are looking for a small block Chevy the ideal motor is a 400. They haven't been made since 1981 so they are a rare find now; but if you cruise poorer areas of town look for a full size car or pick-up with weeds growing all over it that has a 400 on the fender. A safer way of finding one is to buy a BluePrint crate engine:

https://blueprintengines.com/product...etor-bp4002ct1

The 350 is the most popular engine in existence because Chevy made over 27 million of them from 1967 to 2001. It has a 4.00 inch bore so it breathes well with the biggest valves that will fit in a SBC head. Because there were so many made they are still plentiful which makes them cheap. You can pull a TBI equipped SBC 350 out of a pick-up that will still look new inside, even with nearly a 100,000 miles on the odometer. This is because the EFI limits excess fuel that washes the oil on the cylinder walls off, and limits varnish build up in the heads.

When a 350 is rebuilt today it grows into a 383 by stroking it. The difference in price for a different crankshaft is so small compared to the benefits that it is a no brainer. The longer you make the stroke the more torque an engine will build. The other source of growth is displacement, this leads to a BBC.

The problem with a BBC is they are expensive (at least 150% of the cost of a SBC build). This is due to the fact that they are not a common engine, used primarily in light and medium duty trucks. This lack of economy of scale works against you. The other problem is though it is a truck engine (why it is so massive) it was designed as a high performance race car engine for NASCAR racing back in 1961. The design hasn't changed much since then which means it doesn't like today's low octane pump gas. It is very inefficient (dirty) which is why it was banned from cars in 1972, and with unleaded gas it makes half the power it did when it ran on high octane leaded gas. To get the same power of a L-88 427 today you have to nearly double the displacement of the motor. Luckily if you have an armored car full of cash you can do it with a BBC. 805 cubic inch displacements is a common race engine size currently, though the aftermarket is building BBC in excess of 907 cubes today.

Big Dave
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post #3 of 7 (permalink) Old 02-11-2020, 04:04 PM
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My choice would be a small block; either a '383' (basically a 350 'stroked' from 3.5 " to 3.75" as Dave said) or the GM 400. But, a 350 would be just fine if it were not for my bit of a 'lead foot'.

Because the car sat without being 'run' for years, I'd look for a new gas tank. Spectra (a Canadian co.) sells direct replacements (check directly with them to see if they have one for your car). They cost about $200 (non-stainless) and are cheap insurance against 'gunk' from the tank futzing up the fuel system. Look at the fuel lines too. Replace as necessary. Flush rigorously at least. Replace sender with the tank.

Connecting a new engine to an 'old' fuel storage/delivery system is a risk not worth taking (in my opinion).

Pete
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post #4 of 7 (permalink) Old Yesterday, 09:29 AM
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If the 305 is already in there and you just need to do a few things to get it back running again, you may want to go that route for now. If the Gas Tank is in good condition, I would just drain it and start over with fresh gas. It all boils down to what you would prefer. By the way, what kind of car are you working on?

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post #5 of 7 (permalink) Old Today, 08:02 AM
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The cold hard reality is it all comes down to money. Unless your going for a unique look under the hood like a BOP&C engine or W motor, the more cubic inches you can afford the more power you get. With the other engines mentioned you will have to fork out a lot more for the same cubic inches in GM small blocks and big blocks, but a Caddy 500 is still a grunt X2 machine.

383 seems to be the break over where things start to get more expensive when you go bigger in an SBC. 496 for a BBC. Using an aftermarket block I think they are making the small block up to 454 cubic inches, but you will pay more for it than a 500+ cubic inch Big Block. The 406 seems like a reasonably priced SBC and a lot of racers use this, but at the same price you could be into a 496 BBC. So now your looking at weight and all the little extras you will have to by to convert your car from SBC to BBC such as exhaust changes, possible interference with power brake boosters, upgrading front springs to handle the weight...

I personally would not invest in anything less than a 383 in a sbc. Seems like it would be the best bang for the buck if I had the bucks.

Also if your looking for a BBC core to rebuild avoid the tall deck motors as these can also get expensive to build up.
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post #6 of 7 (permalink) Old Today, 08:48 AM
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For what it's worth, buyers remorse can also be a real bummer when it comes to powertrain stuff. When I decided to replace the 396/TH400 in my '68, I certainly looked at small blocks. But if I'm being honest, a 350/TH350 is just kind of boring. It will certainly get the job done, but it doesn't move the needle for me at all. And having buyers remorse about a $7-8k engine and transmission is painful to think about. I'd rather fork over more $$$ for something that makes me giggle like Beavis every time I open the hood. A BBC does that for me. To each, his own though.
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post #7 of 7 (permalink) Old Today, 05:24 PM
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If I were in your shoes, I would absolutely see about getting the 305 running. It shouldn't take you more than 2-4 hours of your time and labor. I am biased though, this is what I did.

If you look at the initial pictures in my old sig line, I bought a car that sat for something like 24 years, put in 2 fuel filters (front and back), changed plugs and oil and points. Didn't take too long.

If you have success, at least you can enjoy it, play with it, and update some things while getting prepared for the eventual motor swap-out. (hopefully with some friends and a fun afternoon!)


I agree with the guys above. I find the 350 very pedestrian these days, but when I needed a replacement motor I got the 383 for the extra torque and I'm very happy with it. (Blueprint brand, bought from JEGs)

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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