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What do you guys think about putting 305 heads on a 350 to up the compression? I've heard of this being done but never tried it; would like some opinions before wasting my time.
4-bolt 350 w/ 305 Heads
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there are hundreds of posts on this site about this exact thing
the 4416 heads are the good ones to modify and run with carb and camshaft ground for carb use. 4416 was basically the most common 1980-86 carb head out there on the 305 engines, trucks and cars both. should be able to get a pair for next to free because they are dirt common. i save any that i come across.
are not swirl port and probably wouldnt do as well with TBI or TPI camshaft, but would work
put bigger valves in and port intake runners and polish exhausts
lots more compression
easy
ive done it and run many this way
works well
the 4416 heads are the good ones to modify and run with carb and camshaft ground for carb use. 4416 was basically the most common 1980-86 carb head out there on the 305 engines, trucks and cars both. should be able to get a pair for next to free because they are dirt common. i save any that i come across.
are not swirl port and probably wouldnt do as well with TBI or TPI camshaft, but would work
put bigger valves in and port intake runners and polish exhausts
lots more compression
easy
ive done it and run many this way
works well
Joined
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17 Posts
Bigger valves as in longer?
no
bigger valve head
1.94 intakes
because most of these 4416 heads had the little 1.84 intake valves
dont put longer valves in
use stock 1.94 OEM valves or what summit racing has
interesting 4416 thread with info
http://www.camaros.net/forums/showthread.php?t=85776
bigger valve head
1.94 intakes
because most of these 4416 heads had the little 1.84 intake valves
dont put longer valves in
use stock 1.94 OEM valves or what summit racing has
interesting 4416 thread with info
http://www.camaros.net/forums/showthread.php?t=85776
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17 Posts
any mods needed to make the 1.94's work? Use stock exhaust valves?
yes have to have shop grind bigger seats into the heads
about 50 to 100 bucks
i have it done to them always so they will flow decently for a bigger engine
i always leave the exhausts alone
but it depends on just how big of an engine youre using them on.
if youre going with a huge SB then you would want to put in bigger exhausts and port the bowls and such...
or just get iron eagles or some other heads instead
about 50 to 100 bucks
i have it done to them always so they will flow decently for a bigger engine
i always leave the exhausts alone
but it depends on just how big of an engine youre using them on.
if youre going with a huge SB then you would want to put in bigger exhausts and port the bowls and such...
or just get iron eagles or some other heads instead
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Putting them on a 4-bolt 350 for my Camaro. Not trying to go too crazy. what size would you recommend for exhaust valves?
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what about dual quads with this setup?
That's just the going rates around here, but that's with cleaning and such. I figured $150 for a VJ is a fair price, even on the rare occasion where I do my own it take me some time to do it and my equipment is pretty bad (hence I rarely do my own).
for valves I would go with 1.94/1.5, maybe 1.6 if you feel like it but not really any need to. Stock 350 valves will work fine for the job. you can get a spring/valve set from competition products for like $125 I believe.
The important thing here is the port work, you need to spend some time on these heads cleaning them up. As cast they'll run out of steam before you hit 5000 RPM- which means no big hp numbers. a good port job goes a long way on these.
for valves I would go with 1.94/1.5, maybe 1.6 if you feel like it but not really any need to. Stock 350 valves will work fine for the job. you can get a spring/valve set from competition products for like $125 I believe.
The important thing here is the port work, you need to spend some time on these heads cleaning them up. As cast they'll run out of steam before you hit 5000 RPM- which means no big hp numbers. a good port job goes a long way on these.
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do a search on this forum for 305 heads on 350. Plenty of people have asked and done it and there are plenty of posts that already covered the topic.
I put a set on my 350 and the engine ran really strong. My 305 heads had 1.94 valves installed. The engine was in a 79 camaro and it quit making power at 5500rpm. I raced it and ran a [email protected] and that was with a 2.73 rear gear.
2:73:1 ? You must have had a good 60ft time. I would have thought the trap speed would have been a little faster. Those rear gear's really held you back.
I'm comparing your's to mine back in 71, 14:90 @ 98mph with 2:87:1.
I'm thinking you had the muffler's on. My 60 ft sucked. I switched to 3:54:1
and knocked off almost .2 off the ET. The biggest problem was the boat anchor cast iron Borg warner tranny that came in the 71 Javelin's. AMC ended up changing to 727's from Chry. Too late for me. The car would have run a lot better at sea level, as Tuscon is higher altitude and conditions were less than good. (low humidity & warm air).
I'm comparing your's to mine back in 71, 14:90 @ 98mph with 2:87:1.
I'm thinking you had the muffler's on. My 60 ft sucked. I switched to 3:54:1
and knocked off almost .2 off the ET. The biggest problem was the boat anchor cast iron Borg warner tranny that came in the 71 Javelin's. AMC ended up changing to 727's from Chry. Too late for me. The car would have run a lot better at sea level, as Tuscon is higher altitude and conditions were less than good. (low humidity & warm air).
I'm thinking the 60ft was 2.100. I shifted at 5000 and 5500rpm and the times stayed the same. I'm thinking the 305 heads ran out of steam at 5000. I didn't do any fine tuning and I was running thru a full exhaust. I installed 3.73's later on, but I ended up selling the car before I could race it again.
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Trying to keep compression low enough to run on pump gas, 90-octane is the best I can get around here. Compression Ratio is something I still dont fully grasp. If I use stock 305 valves & dont port the heads with that raise or lower it?
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Another amateur question:
What does deshrouding involve?
What does deshrouding involve?
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