1970 Chevelle Base - 307 - 350 swap - Chevelle Tech
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post #1 of 56 (permalink) Old Dec 1st, 19, 11:30 PM Thread Starter
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1970 Chevelle Base - 307 - 350 swap

Hello all,

I thought I would start a new thread as the focus has shifted some.

So, I am replacing my 307 with a 350.

With all your wonderful help and guidance here is what I have:
  • I got a good 4 bolt main block
  • 882 castings with 1.94 / 1.50 valves
  • High Energy 260H Hydraulic Flat Tappet Camshaft Complete Kit Lift: .440''/.440" Duration: 260°/260° RPM Range: 1200-5200
  • Rebuild/overhaul master kit with moly rings
  • Edelbrock Single-Quad Performer Manifold and Carburetor Kit for Small Block Chevy 1955-1986 - Performer EPS Intake Manifold, 600cfm Performer Series Carburetor
  • I also bought some tools, got some ball hones, and other stuff.

What else would you all add to this mix?

I have a stock distributor that will be coming out of the 307, don’t know anything about it, thinking about upgrading it – or a waste of cash?
What sort of horses do you all think I could be making at the wheels with this setup?

Last questions:

As this is my first engine pull, rebuild/overhaul, and then install, I am still unsure on the torque converter and flex plate. What will I have to buy or change to get the rebuilt/overhauled 350 to mate up to the TH350? Does anyone have a good torque converter they can recommend? What about a flex plate? Any suggestions? (also I have learned the a flexplate is for an auto and a flywheel is for a manual apparently - I have been saying it wrong for years - didn't even know about a "flexplate." LOL)

Thank you all again!
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post #2 of 56 (permalink) Old Dec 1st, 19, 11:50 PM
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Re: 1970 Chevelle Base - 307 - 350 swap

The 350 will bolt right in place of the 307 but you may want to look for 350 frame stands. You can use the 307 stands but you'll have to transfer the block side motor mounts from the 307. Stock converter and flexplate will work fine.

I would look for an HEI distributor and headers.

The 350 you're building isn't going to set the world on fire but it will be lots of fun. Don't get hung up on what number it will make. That number may depress you but it's plenty to work with for now. The rest of the car isn't ready for a number that will make you proud and if you spend all your money on an engine you won't have any left to replace the weak links that you will undoubtedly find behind it.

70 Camino...Roller

69 Malibu Stock 307, Reverse Manual TH350, 4,500 Stall Edge Converter, 4.56 Spool 35 Spline 12 Bolt

76 C20 VortecPro 496 628HP 655 lb/ft TH400 Edge Converter, 4.10 14 bolt
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post #3 of 56 (permalink) Old Dec 2nd, 19, 7:59 AM
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Re: 1970 Chevelle Base - 307 - 350 swap

That is a good first engine build! It will make a respectable 350 and be fun to drive. You will want eventually upgrade the heads and go with more cam, but for now you have a really good combination considering all the components.
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post #4 of 56 (permalink) Old Dec 2nd, 19, 9:55 AM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

oops, I forgot to include the headers!!!!
  • Hooker Competition Headers 2466HKR
  • I got a good 4 bolt main block
  • 882 castings with 1.94 / 1.50 valves
  • High Energy 260H Hydraulic Flat Tappet Camshaft Complete Kit Lift: .440''/.440" Duration: 260°/260° RPM Range: 1200-5200
  • Rebuild/overhaul master kit with moly rings
  • Edelbrock Single-Quad Performer Manifold and Carburetor Kit for Small Block Chevy 1955-1986 - Performer EPS Intake Manifold, 600cfm Performer Series Carburetor
  • I also bought some tools, got some ball hones, and other stuff.
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post #5 of 56 (permalink) Old Dec 2nd, 19, 9:56 AM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

Quote:
Originally Posted by 1975TypeS-3 View Post
That is a good first engine build! It will make a respectable 350 and be fun to drive. You will want eventually upgrade the heads and go with more cam, but for now, you have a really good combination considering all the components.
I am willing to go with more cam as I can return the one I bought pretty easily. Any suggestions on a better or hotter cam? I want to stay with a reliable car and a good streetcar, but looking for lots of low-end torque
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post #6 of 56 (permalink) Old Dec 2nd, 19, 11:21 AM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

Okay,

So I got ahold of comp cams and summit this morning. I learned you better be ready for comp, they gets lots of questions and I think I irritated the guy to death - poor guy. I apolgized prfusily.

Both tech guys reconmended:

https://www.jegs.com/i/COMP-Cams/249/K12-234-2/10002/-1

https://www.summitracing.com/parts/c...34-2/overview/

The said that it would make more power for me than:
https://www.jegs.com/i/COMP-Cams/249/K12-206-2/10002/-1

So I trust you all as you actually have used all this stuff. With my setup - what do you think will be best:
  • High Energy 260H Hydraulic Flat Tappet Camshaft Complete Kit Lift: .440''/.440" Duration: 260°/260° RPM Range: 1200-5200

or
  • Xtreme Energy 256H Hydraulic Flat Tappet Camshaft Complete Kit Lift: .447"/.454" Duration: 256°/268° RPM Range: 1000-5200


THANK YOU ALL - I apologize if I am being irritating - just learning
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post #7 of 56 (permalink) Old Dec 2nd, 19, 1:10 PM
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Re: 1970 Chevelle Base - 307 - 350 swap

The Xtreme Energy would be a better choice because of the extended exhaust duration - helps make up for the weak exhaust port on the stock heads.
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post #8 of 56 (permalink) Old Dec 2nd, 19, 1:28 PM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

Quote:
Originally Posted by 1975TypeS-3 View Post
The Xtreme Energy would be a better choice because of the extended exhaust duration - helps make up for the weak exhaust port on the stock heads.
Okay,
This is the consensus I am getting -thank you! I will ship the other back to Jegs, and order Xtreme from summit.

Let's talk distributors - what brand do you all like for SBC? I am new to them so please forgive my ignorance. I want a good hot spark - what would you all choose?
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post #9 of 56 (permalink) Old Dec 2nd, 19, 1:45 PM
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Re: 1970 Chevelle Base - 307 - 350 swap

Quote:
Originally Posted by Tommy the Cat View Post
The 350 will bolt right in place of the 307 but you may want to look for 350 frame stands. You can use the 307 stands but you'll have to transfer the block side motor mounts from the 307. Stock converter and flexplate will work fine.

I would look for an HEI distributor and headers.

The 350 you're building isn't going to set the world on fire but it will be lots of fun. Don't get hung up on what number it will make. That number may depress you but it's plenty to work with for now. The rest of the car isn't ready for a number that will make you proud and if you spend all your money on an engine you won't have any left to replace the weak links that you will undoubtedly find behind it.

ABSOLUTELY, TOTALLY, COMPLETELY AGREE!!!!!!!!!!!!!!!!!!!!!!
Replace the engine mount brackets on the front cross member with 350-454 style brackets, then use good rubber engine mounts for a 350-454.
You CAN use the bone stock 307 distributor (SB and BB distributors are a 100% interchange), but find a good distributor person and have it recurved. OR, you can do a so-so job yourself with a hand held dwell meter and a dial back timing light. Either use a set of heavy duty points, or, install an electronic conversion such as a PerTronix.
I refuse to comment on the tranny, because automatic transmissions are against my religion, and I do not want to offend my pastor!!!

Tom Parsons
TC# 474
#3 FOREVER!!!!!
Light travels faster than sound. That is why some people appear to be bright until you hear them speak. (unknown)
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post #10 of 56 (permalink) Old Dec 2nd, 19, 2:15 PM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

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Originally Posted by DZAUTO View Post
ABSOLUTELY, TOTALLY, COMPLETELY AGREE!!!!!!!!!!!!!!!!!!!!!!
Replace the engine mount brackets on the front cross member with 350-454 style brackets, then use good rubber engine mounts for a 350-454.
You CAN use the bone stock 307 distributor (SB and BB distributors are a 100% interchange), but find a good distributor person and have it recurved. OR, you can do a so-so job yourself with a hand held dwell meter and a dial back timing light. Either use a set of heavy duty points, or, install an electronic conversion such as a PerTronix.
I refuse to comment on the tranny, because automatic transmissions are against my religion, and I do not want to offend my pastor!!!
LOL - against your religion! It is what I have to work with for now - I will swap it over one day if funds, time, and the stars line up. I love a standard transmission.

So, pretty much my 350 will bolt right up in place of the 307? You said to get new engine mount brackets and good rubber engine mounts - do you guys have any suggestions? What has worked for you all?
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post #11 of 56 (permalink) Old Dec 2nd, 19, 2:48 PM
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Re: 1970 Chevelle Base - 307 - 350 swap

Quote:
Originally Posted by s1nemesis1s View Post
LOL - against your religion! It is what I have to work with for now - I will swap it over one day if funds, time, and the stars line up. I love a standard transmission.

So, pretty much my 350 will bolt right up in place of the 307? You said to get new engine mount brackets and good rubber engine mounts - do you guys have any suggestions? What has worked for you all?

The 307 engine stands (brackets on the cross member) are TALLER than 350-454 brackets and they DO NOT mate well with 350-454 rubber engine mounts. Plus, the 307 rubber engine mounts are not as "robust" as the 350-454 engine mounts. SOOOOOOOOOOOOOO, if you choose to stay with the 307 frame brackets, you MUST use the weaker 307 rubber engine mounts.


Chances are very good that you can locate the 350-454 frame brackets from someone right here on Team Chevelle (try classified ads). The brackets CAN BE swapped with the engine in the car------------BUT IT IS A MAJOR PAIN!!!!!!!!!! If you swap to 350-454 brackets, do it when the engine is out.
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Tom Parsons
TC# 474
#3 FOREVER!!!!!
Light travels faster than sound. That is why some people appear to be bright until you hear them speak. (unknown)
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post #12 of 56 (permalink) Old Dec 2nd, 19, 4:50 PM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

Quote:
Originally Posted by DZAUTO View Post
The 307 engine stands (brackets on the cross member) are TALLER than 350-454 brackets and they DO NOT mate well with 350-454 rubber engine mounts. Plus, the 307 rubber engine mounts are not as "robust" as the 350-454 engine mounts. SOOOOOOOOOOOOOO, if you choose to stay with the 307 frame brackets, you MUST use the weaker 307 rubber engine mounts.


Chances are very good that you can locate the 350-454 frame brackets from someone right here on Team Chevelle (try classified ads). The brackets CAN BE swapped with the engine in the car------------BUT IT IS A MAJOR PAIN!!!!!!!!!! If you swap to 350-454 brackets, do it when the engine is out.
Here is what I have come up with:

https://www.summitracing.com/parts/arp-130-3102
https://www.summitracing.com/parts/arp-130-3105
x2 https://www.summitracing.com/parts/dos-a2283
https://www.summitracing.com/parts/opg-97ch001
https://www.summitracing.com/parts/sum-g104sfi
https://www.summitracing.com/parts/hup-gm20
https://www.summitracing.com/parts/sum-910219
https://www.summitracing.com/parts/hup-hp7455c - do I need two of these?




Wife gave me a 500 gift card for summit for early xmas - so this is what I am ordering. I want it to go smooth and simple.
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post #13 of 56 (permalink) Old Dec 2nd, 19, 4:52 PM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

Also, I assume I want a new distributor with a vacuum advance? I have never dealt with the others, and from my understanding vacuum advance is better for cruising.
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post #14 of 56 (permalink) Old Dec 2nd, 19, 6:29 PM
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Re: 1970 Chevelle Base - 307 - 350 swap

Quote:
Originally Posted by s1nemesis1s View Post
Also, I assume I want a new distributor with a vacuum advance? I have never dealt with the others, and from my understanding vacuum advance is better for cruising.

That is EXACTLY correct. For a street/driver, you want a vac adv distributor.
There is nothing wrong with an HEI distributor, but personally, I just do not like the big size of them. For low maintenance and a good driver, it's hard to beat a properly built and curved point type distributor. Although, I do feel that an upgrade to an electronic conversion, such as PerTronix is good, plus a good oil filled higher output coil is good.
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post #15 of 56 (permalink) Old Dec 3rd, 19, 10:26 AM Thread Starter
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Re: 1970 Chevelle Base - 307 - 350 swap

I am looking at the pertronix units but I will probably wait a bit. I am wanting to get the main stuff to build this thing with.
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