Chevelle Engine Update

"MM54" (mm54mk2) 10/04/2018 at 22:10 • Filed to: '71Chevelle

8

33

Doesn’t look much different than last time, but it’s much closer to coming out now.

Recap: Since the original 307 is very tired, I decided to build a 350 for the Chevelle to swap in while conveniently having the rest of the front end apart for some cleaning / repairs. This process started by buying a used 350 which I intended to do a simple rebuild on with some good heads and a cam and be ready to go. Things have not gone to plan.

When I tore down the engine, I found it had been rebuilt before. The piston/bore clearance was at a maximum, and there was rust pitting in #2. This means it needs bored out, which also means buying pistons. Not the end of the world. When I took the bottom end apart, I found a mis-match of a couple different styles of (factory) rods and quite a bit of bearing wear. Not great.

I spoke with the machine shop today, where the block has been cleaned and pressure tested (it passed). It needs a line hone and, while he hasn’t measured the bores yet, we agree it sure looks like it needs bored out. The crank has been cleaned and needs polished at a minimum (hadn’t looked closely enough yet to see if it would need a grind).

Since nobody reads posts like this that are rambling walls of text, congratulations on making it this far.

While on the phone, we both reached the same conclusion - I’m buying pistons, I’m buying rods, and the crank needs work. Why not just stroke it? The only difference is that I need a different flywheel than I have now; otherwise it’s buying parts I would have been buying anyways and a new crank (instead of machine work on the old one). This adds cost (the whole point of the donor 350 was to not have to buy bottom-end parts but that went out the window a while ago ) but, hey, now I’m b uilding a 383.

RallyDarkstrike - Fan of 2-cyl FIATs, Eastern Bloc & Kei cars > MM54 10/04/2018 at 22:25

0

I’m not a muscle car guy at all, so forgive my ignorance, but if the point of this was to save money and you’ve had to do all this work to the ‘new’ replacement engine, and the old one was only ‘tired’ and didn’t have problems this bad...wouldn’t it have been cheaper to fix up the old one? I know, not as much power had you done so though, of course!

shop-teacher > MM54 10/04/2018 at 22:28

1

Stroker motor!

lone_liberal > MM54 10/04/2018 at 22:33

1

Nothing at all wrong with the 383! That should give you some nice torque to play with.

Jordan and the Slowrunner, Boomer Intensifies > RallyDarkstrike - Fan of 2-cyl FIATs, Eastern Bloc & Kei cars 10/04/2018 at 22:39

7

There isn’t much you can do with a 307.

MM54 > lone_liberal 10/04/2018 at 23:01

0

For sure. If I were to buy an engine (no fun in that, though) it’d be one of Blueprint’s 383s. The long-term idea had been do the cheap rebuild now, then when it blew up do the stroker but I guess circumstance is led to skipping a step in there and paying out all the money now!

I also briefly considered building a smallblock 400 for it, which would be interesting but not as easy to find a core, plus the heads need steam holes and so on. The 383 is a good middle ground. Enough torque to be a lot of fun on the street without immediately breaking the trans/diff.

MM54 > shop-teacher 10/04/2018 at 23:02

2

Exciting in all ways except for my wallet, which thought it was getting off easy by not buying bottom-end parts. Still looking forward to it, though.

MM54 > Jordan and the Slowrunner, Boomer Intensifies 10/04/2018 at 23:04

0

I mean, there is, but not on a performance-per-dollar level anywhere near a 350. There have been some cool 307s built; it’s just a pre-stroked 283 ;)

MM54 > RallyDarkstrike - Fan of 2-cyl FIATs, Eastern Bloc & Kei cars 10/04/2018 at 23:07

1

At a minimum the 307 would need a bore/hone, new pistons, heads/cam, and the other usual rebuild stuff (bearings, seals, etc), possibly more . At the end of the day I’d have anywhere from 60-10 0% of the cost of doing the 350/383 into an engine making 65% (generously) the power. Just not much sense in it that way. The block might make a good coffee table, though!

ITA97, now with more Jag @ opposite-lock.com > MM54 10/04/2018 at 23:13

0

In the end, how is this going to compare (dollar wise) to just ordering a (on the milder side) 350 crate motor from the GM performance parts catalog?

lone_liberal > MM54 10/04/2018 at 23:19

0

I’ve been looking at the Blueprint 383s too, for the far distant time when my Camaro is ready for something better than the pitiful smog motor it has. I also found a local place that has 383s that’s a possibility too.

https://westcoastengines.com/383-stroker/

someassemblyrequired > MM54 10/04/2018 at 23:19

2

I have an unhealthy desire to swap the 2.0 turbo Ecotec/6 speed out of the current Camaro into a vintage A-body just because I am a terrible person.

Though a 383 will be a riot.

My bird IS the word > MM54 10/05/2018 at 02:03

1

Given that its a chev 350, also not your orig 350, why not buy a new blueprint engine? Seems like similar money and infinitely less hassle.

RallyDarkstrike - Fan of 2-cyl FIATs, Eastern Bloc & Kei cars > MM54 10/05/2018 at 06:49

1

Ah, I getcha.

LimitedTimeOnly @ opposite-lock.com > MM54 10/05/2018 at 07:08

1

“ Since nobody reads posts like this that are rambling walls of text, congratulations on making it this far.”

Thanks!

I’m looking forward to helping a friend rebuild his dad’s chevelle. He had a 308 ready to go, but got a 454 that we just started stripping down for a rebuild. Should be fun.

arl > MM54 10/05/2018 at 07:10

1

No substitute for cubic inches! 383 should rock.

shop-teacher > MM54 10/05/2018 at 07:11

1

Such is life when tearing into old cars. At least you'll get something for that money.

pip bip - choose Corrour > MM54 10/05/2018 at 07:12

0

should’ve bought a crate 502

:P

Hamtractor > MM54 10/05/2018 at 08:52

1

Speaking of tired, that steering box is looking like an Exxon Valdez survivor...

Duck Duck Grey Duck FTMFW! > MM54 10/05/2018 at 11:46

1

Hell yeah!!! Saying it has a 383 sounds cooler anyways. Might as well get aluminum heads too!!! ; P

Duck Duck Grey Duck FTMFW! > Jordan and the Slowrunner, Boomer Intensifies 10/05/2018 at 11:47

1

Boats need anchors.

MM54 > Duck Duck Grey Duck FTMFW! 10/05/2018 at 18:28

1

It will have aluminum heads and a good cam, appropriately matched for being a street car .

MM54 > Hamtractor 10/05/2018 at 18:29

0

Yeah I’m not sure what the deal is with it. In the many years I’ve had the car it hasn’t leaked a drop. The whole car is undercoated heavily, but this is m ore grease than rubber, so I really don’t know what the idea was. Someone wanted to grease the steering, I guess.

MM54 > pip bip - choose Corrour 10/05/2018 at 18:29

1

no

MM54 > shop-teacher 10/05/2018 at 18:30

1

For sure. Should be a lot of fun until I break the transmission and/or diff!

MM54 > LimitedTimeOnly @ opposite-lock.com 10/05/2018 at 18:31

1

I considered going big block (had a friend selling a 454 out of an early 80's step van) but the extra cost and weight isn’t really worth it for what I’m doing. Still always cool to see those wide valve covers when you pop the hood, though!

MM54 > My bird IS the word 10/05/2018 at 18:32

0

Very similar cost (mine should be a hair cheaper) but there’s no fun in buying an engine when you could have built it. I guess that’s the modern-day mentality though - why fix something when you can throw it away and buy something new.

MM54 > someassemblyrequired 10/05/2018 at 18:34

0

That actually would be pretty neat. Would upset a lot of the old folk but that’s usually a good thing. I say find a roller and go for it!

MM54 > ITA97, now with more Jag @ opposite-lock.com 10/05/2018 at 18:34

1

Cheaper and way better performance.

My bird IS the word > MM54 10/05/2018 at 20:31

0

Mine' more risk mitigation, why risk something going wrong or the time involved when you can buy something with a warranty? If I didn't have hood fitment issues I'd be all over that.

sdwarf36 > MM54 10/05/2018 at 23:00

1

<— Automot ive machinist here. Questioning the 'need' for a line bore/hone. Chevy's don't usually have any issue. But I know some shops have their  ' thing' they like to do-so ok-it can't hurt i guess.

Just beware-making a 383 requires some clearancing for the extra stroke on the bottom of the bores. Its a fit- clearance-refit deal.  #6? cylinder is the worse offender.

Also-go buy a steering box for a 1979 trans am. They’re cheap and improve the steering 1000%. Seriously-I’ve done it a bunch of times. Same box fits all GM front steer cars from ‘64 to like ‘84.

someassemblyrequired > MM54 10/05/2018 at 23:07

1

I did some googling, and apparently Chevy already did it, but with a ‘67 Nov a :

Would be fun with the right car and probably a wrecked Sky Redline or Camaro. No way you’d do it with a crate engine when a hotted up 350 crate motor is half the price of a turbo 4 .

MM54 > sdwarf36 10/05/2018 at 23:55

0

This machine shop has been building street and race engines since the 60s so I trust the owner when he says it ought to be line honed. Sure, could probably get away without it but if it’ll last longer nicely aligned, why not.

10 years ago the hot swap in steering gear was the box from a jeep grand cherokee, which bolts right in (same pitman arm and even rag joint) with SAE/metric adapters on the power steering line fittings. Last I heard, quality remans of these are getting hard to find; not sure what the current bang-for-your-buck swap is, but I’ll keep the ‘79 trans am in mind - thanks!

shop-teacher > MM54 10/06/2018 at 10:50

1

Pretty much, yeah :)