how much differance will these heads make to my 305?
Thread Starter
Senior Member
Joined: Feb 2006
Posts: 535
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From: ft.wayne indiana
Car: 84 camaro
Engine: 72 chevy 406 sbc
Transmission: 700r4
Axle/Gears: 3.42 eaton posi
how much differance will these heads make to my 305?
early70s camel hump heads with 194/1.6 62cc what will this do to my L69 305? guy at work want $250 for them thinkin bout buying them any help appreciated guys ,thanks
Thread Starter
Senior Member
Joined: Feb 2006
Posts: 535
Likes: 0
From: ft.wayne indiana
Car: 84 camaro
Engine: 72 chevy 406 sbc
Transmission: 700r4
Axle/Gears: 3.42 eaton posi
well it runs mid 14s all stock rebuild ,only exhaust mod is hollow cat and flowmaster muffler. no real goal but he has these heads on a stock 350 and it runs mid 12s in a chevy s-10 with 4.11 so i was just wondering what they could do for me?
TGO Supporter
Joined: Jan 2005
Posts: 1,768
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From: Gambrills, Md
Car: clapped out 84Z
Engine: 355 efi roller
Transmission: tremec TKO
Skip the heads and get headers. Put a pipe in your hollow cat while you're at it, it will flow better. Upgrade to a 3" cat-back. If that isn't enough get a decent cam and intake.
And get a posi, a one-legged dog goes no-where fast!!
And get a posi, a one-legged dog goes no-where fast!!
Member
Joined: Mar 2004
Posts: 430
Likes: 1
From: Huntsville Alabama
Car: 89 IROC convert.
Engine: tpi 305
Transmission: T-5
Axle/Gears: 3.42 10 bolt
I agree. You'll lose a little compression, and unless the heads have been worked over good, the guides and valvestems are probably shot. Lots of people rebuild heads and knurl the guides. It's a very short term fix and the valves are loose again in a few thousand miles.
If they are 186 castings, and they probably are if they are double humps with accessory holes, then they were not originally built to withstand unleaded gas. This means that the exhaust valves eventually wears down the exhaust seats and hurts flow. However, hardened seats and SS exhaust valves can be installed, and if these have 1.60s it may have been done, though it doesn't happen very often. Double check the exhaust diameter.
186 castings could be had with 1.94/1.50 valves or 2.02/1.60s and showed up on lots of 327s and 350s in the 60s and early 70s and on everything from 2 barrel malibus to the DZ302 motor in the early z28s. The collectors like them, and that's who would be better off with them. BTW 250.00 is about what they are worth. So its no smoking deal. I've sold sets for 200.00 that needed work.
What would it do for you? Hard to tell. The s-10 is considerably lighter, and the 4.11 screws would give it a real advantage.
Don't expect a huge jump, say into the 13s. You might even lose a bit depending on their condition.
Headers or posi/gears for the same money will definitely be money better spent.
If they are 186 castings, and they probably are if they are double humps with accessory holes, then they were not originally built to withstand unleaded gas. This means that the exhaust valves eventually wears down the exhaust seats and hurts flow. However, hardened seats and SS exhaust valves can be installed, and if these have 1.60s it may have been done, though it doesn't happen very often. Double check the exhaust diameter.
186 castings could be had with 1.94/1.50 valves or 2.02/1.60s and showed up on lots of 327s and 350s in the 60s and early 70s and on everything from 2 barrel malibus to the DZ302 motor in the early z28s. The collectors like them, and that's who would be better off with them. BTW 250.00 is about what they are worth. So its no smoking deal. I've sold sets for 200.00 that needed work.
What would it do for you? Hard to tell. The s-10 is considerably lighter, and the 4.11 screws would give it a real advantage.
Don't expect a huge jump, say into the 13s. You might even lose a bit depending on their condition.
Headers or posi/gears for the same money will definitely be money better spent.
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