Thread: Chevy 350 or 427

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This may be a little random and I appologize in advance.

I have a 1969 Chevrolet C20 (for parts) and a 1970 C10 long bed that I'm currently restoring / customizing.The 1970 currently has a crate 350 under the hood with a three on the tree. I am considering switching to a 427 would I be better off to stick with the 350 or would it be difficult to switch to a 427 (changing from a small block to a big block). I'm guessing ill have to change the rear end and transmission on the truck to compensate for the 427.

With the 350 I am averaging 3k rpms at 55-65 mph depending on the incline. I'm guessing with the current gearing and what not I would be burning rubber in third gear with a 427.

Originally Posted by Lefcrak

This may be a little random and I appologize in advance.

I have a 1969 Chevrolet C20 (for parts) and a 1970 C10 long bed that I'm currently restoring / customizing.The 1970 currently has a crate 350 under the hood with a three on the tree. I am considering switching to a 427 would I be better off to stick with the 350 or would it be difficult to switch to a 427 (changing from a small block to a big block). I'm guessing ill have to change the rear end and transmission on the truck to compensate for the 427.

With the 350 I am averaging 3k rpms at 55-65 mph depending on the incline. I'm guessing with the current gearing and what not I would be burning rubber in third gear with a 427.

First & foremost, WELCOME! We're glad to have you here . Working from memory, I believe the only things that change between those motors (as far as getting it into the truck) are the mounts and they're location(s).. As far as which would be better.. that is purely an owner decision. A "hot rodder" will love the torque and horsepower of the big block. But the 350 is no slouch and if it's a new(er) crate motor, then maybe the wiser choice is to stick with it!?!?! Again, that choice is on you. I am not certain that you'd "NEED" to swap tranny and final drive just because of the big block, it would depend on what the truck already has for those parts.

You could also replace the ring and pinion by itself and get your truck into a "more user friendly" range of rpm's. If your not using it as a truck and carrying or towing daily this may be beneficial to your motor and your wallet.

Other guys will be along and offer other opinions, keep an open mind and be honest with yourself and what you want the truck to do and you won't go wrong!

Welcome-----If I remember right, isn't Eagle River uphill from Ancorage??????????Always was amazed at the glaciers flying into/outta Ank and Fairbanks-------

For a pure dollar choice, staying with a small block 350x would make things such as mounts, exhaust,etc simpler----if you are considering straying from sbc I would suggest taking a good look at a lift out package(engine/trans/accessories((alt, ac. ps))
of one of the late model trucks---example--5.3 with auto overdrive trans---fuel injection---economy and performance plus drivability will go way up---and it will adjust for the altitude differances as you climb the hills----

Yes Eagle River is just a few miles out side of Anchorage. There is a hill as you cross the river. The only reason I was asking about the 427 is I love the way it sounds, feels, and was told I can get better fuel mileage plus power if the engine is done right. It is 2wd and no power anything brakes, steering ect. So it has plenty of space under the hood.
I want to use it at the local drag strip during the flag drags ('74 and older only) for show and to race (one day out of the year). Then double as my sunny day driver.
If I change my transmission I will have to get a new floor pan because the three on the tree has a flat floor pan.

It is a newer crate engine but I think I need to do a major over haul on it. The last time I drove it the the driver side of the engine seemed to be mis firing and loosing power. There was also a thick grey white smoke coming out of the driver side exhaust pipe it has over 200,000 miles on it.

There is a guy here in town that if I give him my current engine (4 bolt main 350 it hasn't been driven since 1981 and is seized up) from my 69' c20 he will give me a completely rebuilt 350 in its place or give me a deal on a 427. So I'm stuck with the decision of a throaty deep rumble and power of a 427, or just keep rolling with what I have.

I have two goal for this truck only one of them will be achieved. One is to have a sleeper that's had it's paint buffed off get a slight rust color in spots and clear coat it. The other is to have a beautiful show truck black with a bright red pearlescent top coat.

Yo I can speak for me doing it once vs doing it 3 or more time to get that final product is a beast on the pockets... I would go big on the motor that way your sleeper and your show truck is covered. Just me tho....

Originally Posted by jerry clayton

Welcome-----If I remember right, isn't Eagle River uphill from Ancorage??????????Always was amazed at the glaciers flying into/outta Ank and Fairbanks-------

For a pure dollar choice, staying with a small block 350x would make things such as mounts, exhaust,etc simpler----if you are considering straying from sbc I would suggest taking a good look at a lift out package(engine/trans/accessories((alt, ac. ps))
of one of the late model trucks---example--5.3 with auto overdrive trans---fuel injection---economy and performance plus drivability will go way up---and it will adjust for the altitude differances as you climb the hills----

A newer 5.3 would be cool but I would rather keep all the computers and electronics out of the truck. The only power my truck uses is the gauges and lights. It currently doesn't even have a stereo in it.

Originally Posted by Gmuscle

Yo I can speak for me doing it once vs doing it 3 or more time to get that final product is a beast on the pockets... I would go big on the motor that way your sleeper and your show truck is covered. Just me tho....

That's kind of the direction I'm heading. There is plenty of work to do on my truck before it gets to show quality. A few spots of cancer on the bed and I have to replace the rocker panels. I plan to rebuild it from the ground up as soon as I find a garage big enough to do it.

I can dig it I'm on my second my self so things I learned from the 1st implement those with the new build and extend the deadline cuz you don't want to rush anything.

Originally Posted by Gmuscle

I can dig it I'm on my second my self so things I learned from the 1st implement those with the new build and extend the deadline cuz you don't want to rush anything.

That's the beauty of my truck I have no deadline just having fun and if I can get it done in a decent amount of time I will buy and rebuild a Chevelle or camaro for my wife

Like the old saw says: Go big, or go home.

Build the 427 right and it will be stout, and nearly bulletproof; stick a 4 speed and a well built rear end behind it and go have more fun than ought to be allowed.

Originally Posted by Rrumbler

Like the old saw says: Go big, or go home.

Build the 427 right and it will be stout, and nearly bulletproof; stick a 4 speed and a well built rear end behind it and go have more fun than ought to be allowed.

What would a well built rear end consist of. The gear box has different mounts on it than a normal gear box since its on long swing arms. Can I just change out the gears or do I need to get a whole new rear end?

Originally Posted by Lefcrak

What would a well built rear end consist of. The gear box has different mounts on it than a normal gear box since its on long swing arms. Can I just change out the gears or do I need to get a whole new rear end?

To my way of thinking, a 12 bolt would be the best of all choices, and a 10 bolt a close second. However, I don't know just when GM went to them in the trucks. Since your truck is a C20, the original rear end will probably hold up to a fair amount of oomph; depending on what the first gear ratio of your tranny is, something in the neighborhood of 3.90 or 4.10:1 rear end ratio would be fair.

the truck he;s building is a C10-----------

with todays fuel prices---why don't you do a math problem????? how many miles you'll drive it per year and what your fuel cost will be at different MPGallon????? then build it toward a favorable number----------

Originally Posted by Rrumbler

To my way of thinking, a 12 bolt would be the best of all choices, and a 10 bolt a close second. However, I don't know just when GM went to them in the trucks. Since your truck is a C20, the original rear end will probably hold up to a fair amount of oomph; depending on what the first gear ratio of your tranny is, something in the neighborhood of 3.90 or 4.10:1 rear end ratio would be fair.

As Jerry pointed out I'm rebuilding the c10 I don't know what's worth salvaging as far as mechanical parts from the c20. The c10 was an old farm truck so it's geared to pull rather than go highway speeds or above