is it worth doing? head and intake swap - Chevelle Tech
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post #1 of 16 (permalink) Old Aug 12th, 19, 11:26 PM Thread Starter
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is it worth doing? head and intake swap

pretty sure I asked a while back. motor is a basic mid 70s 350. it's got the stock 72cc heads, Elgin cam that's specs like a performer cam .420 lift. performer intake with a 3310 holley and headers.
I have a set of 1.94/1.50 461 camel hump heads and a rpm intake I want to install
what say the experts? will I feel any real difference with just the 2 changes? Parts are just sitting on the shelf, only thing I need to buy is a set of plugs.
rest of the combo, wide ratio muncie, 3.55 gears. jim

Jim

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post #2 of 16 (permalink) Old Aug 13th, 19, 2:34 AM
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Re: is it worth doing? head and intake swap

I know its not what you have but Id throw a set of vortec heads on it. Seems Gen 1 sbc stuff is getting cheaper all the time.
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post #3 of 16 (permalink) Old Aug 13th, 19, 6:43 AM
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Re: is it worth doing? head and intake swap

Quote:
Originally Posted by Jim Mac View Post
pretty sure I asked a while back. motor is a basic mid 70s 350. it's got the stock 72cc heads, Elgin cam that's specs like a performer cam .420 lift. performer intake with a 3310 holley and headers.
I have a set of 1.94/1.50 461 camel hump heads and a rpm intake I want to install
what say the experts? will I feel any real difference with just the 2 changes? Parts are just sitting on the shelf, only thing I need to buy is a set of plugs.
rest of the combo, wide ratio muncie, 3.55 gears. jim
You will see a conservative difference from the bump in compression. Unless you ccd or milled your heads, they are likely 76 cc or larger. You will see less of a difference than someone with too big of cam for compression or too small of stall/gear since your manual trans helps you cover up the small lose of low end you may have. You will probably see a small gain from the intake too, especially if its an Air Gap.

For what it is worth, when I switched from 882 casting 1.94s to 461 casting 1.94s, my ET dropped from 14.15 to 13.51 and mph increased from 98 to 101.5 - no other changes. This was a cast flat top 355 with a 280/480 Wolverine Cam, Weiand X-CELerator intake (with divider installed), Holley 3310, 4.10 gears, and stock 1976 Camaro stall converter.

The way the car launched with the increased compression made the difference. The engine did not bog previously, it was just lazy. The cam really liked the added compression considering the cam really wanted a 3500 stall converter. You will not notice as large of difference since your cam and manual transmission seem to be better matched to your compression.

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post #4 of 16 (permalink) Old Aug 13th, 19, 7:57 AM Thread Starter
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Re: is it worth doing? head and intake swap

I did the vortec swap on my nova a few years ago. unfortunately it's over $1200 by the time you buy everything for the swap. the 66 will eventually get a 454 probably next summer, I'm just trying to use the parts I have on hand. That let's me clear up a little more shelf space when the smog heads go to the dump. jim

Jim

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post #5 of 16 (permalink) Old Aug 13th, 19, 8:21 AM
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Re: is it worth doing? head and intake swap

Minimal cost for the swap. Take it to a track first. If the heads are not milled you will go from 72 cc to 64 cc. Steel shim head gasket you will get more compression. You could switch cam at this time easily. RPM 2200- 5500 .050 Intake / Exhaust Duration 224/224 Intake / Exhaust Lift .450/.460 Lobe Sep 114. I have used this a few times. Drives good and sounds good.


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post #6 of 16 (permalink) Old Aug 13th, 19, 6:27 PM Thread Starter
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Re: is it worth doing? head and intake swap

I'd love to do a cam swap, but theres a 454 on the stand with new bearings and rings installed. Got a set of 063 heads, rpm intake, gm flywheel for it. so when I buy a cam kit, it's going to be for the 454. jim

Jim

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post #7 of 16 (permalink) Old Aug 13th, 19, 6:54 PM
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Re: is it worth doing? head and intake swap

This is in your 66?


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post #8 of 16 (permalink) Old Aug 13th, 19, 7:47 PM
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Re: is it worth doing? head and intake swap

It's worth it to get rid of the smog heads (882?) especially since it will only cost a few dollars.

I had an almost identical engine combo with a TH350, stock converter and 3.73s in my Camino at one point and it ran darn good but wanted more converter.

I vote do it. But give us a before/after time slip if you can.

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post #9 of 16 (permalink) Old Aug 13th, 19, 10:19 PM Thread Starter
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Re: is it worth doing? head and intake swap

yes, for the 66 chevelle. need to edit my signature, the el camino is gone. If I can deal with the hungry mosquitos, I'm hoping to have the motor apart tomorrow afternoon. jim

Jim

70 chevelle, SS clone 454 4 speed
71 camaro. (owned since 1978!) 6-71 blown small block 400
66 chevelle 350 4 speed 3.55 12 bolt
66 el camino 350 th350 parts hauler
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post #10 of 16 (permalink) Old Aug 14th, 19, 6:52 AM
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Re: is it worth doing? head and intake swap

Quote:
Originally Posted by Jim Mac View Post
pretty sure I asked a while back. motor is a basic mid 70s 350. it's got the stock 72cc heads, Elgin cam that's specs like a performer cam .420 lift. performer intake with a 3310 holley and headers.
I have a set of 1.94/1.50 461 camel hump heads and a rpm intake I want to install
what say the experts? will I feel any real difference with just the 2 changes? Parts are just sitting on the shelf, only thing I need to buy is a set of plugs.
rest of the combo, wide ratio muncie, 3.55 gears. jim
I did that same swap to a '74 Laguna S3 350 back in '76. Wasn't worth the time. Compression change was maybe 1/2-3/4 point, you didn't notice anything seats of the pants. That motor has dished pistons, small valve reliefs, no quench area, etc., etc. 1981 I bought a '73 Vette with the L48 350, same setup, dished piston with the 76cc heads. Put in a set of domed replacement pistons for the 11/1 motors, that made a big difference.

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post #11 of 16 (permalink) Old Aug 14th, 19, 7:10 AM
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Re: is it worth doing? head and intake swap

Quote:
Originally Posted by Jim Mac View Post
I'd love to do a cam swap, but theres a 454 on the stand with new bearings and rings installed. Got a set of 063 heads, rpm intake, gm flywheel for it. so when I buy a cam kit, it's going to be for the 454. jim

Okay, some new info here that changed my response. Was going to say to go for it or better yet upgrade to the vortec heads or lower cost aluminum. However now that I know there is a BBC swap already being assembled I'd say live with what you have and use the effort, dollars, time to get the big block swap going!
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post #12 of 16 (permalink) Old Aug 14th, 19, 7:44 AM
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Re: is it worth doing? head and intake swap

I doubt you'll notice much change. Sell or trade the parts and plan for the BB swap.
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post #13 of 16 (permalink) Old Aug 14th, 19, 7:51 AM
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Re: is it worth doing? head and intake swap

I would do the swap but also go with a different cam. If it was me I'd go with a .480 lift.

https://www.jegs.com/i/COMP-Cams/249...791+4294829484
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post #14 of 16 (permalink) Old Yesterday, 4:38 PM
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Re: is it worth doing? head and intake swap

Quote:
Originally Posted by Tommy the Cat View Post

I vote do it. But give us a before/after time slip if you can.
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post #15 of 16 (permalink) Old Yesterday, 4:50 PM
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Re: is it worth doing? head and intake swap

Quote:
Originally Posted by Jim Mac View Post
I'd love to do a cam swap, but theres a 454 on the stand with new bearings and rings installed. Got a set of 063 heads, rpm intake, gm flywheel for it. so when I buy a cam kit, it's going to be for the 454. jim
IMHO not worth your time. The cam that's in the engine is too small to take advantage of the new parts.

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