If the heads are off the engine? The open chamber heads have a circular combustion chamber. The closed chambers have a flat section oposite the spark plug hole.
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2. are the exhaust bolts the same
Yes. 302 and 351 are the same if 2V. 2V and 4V are different. 4V has very very large ports. They are obvious. Most engines are 2V though.
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3. how do the 302 and 351 heads differ?
Just the combustion chamber and the 2V-->4V differences.
Yes. 302 and 351 are the same if 2V. 2V and 4V are different. 4V has very very large ports. They are obvious. Most engines are 2V though.
Brenden
Not wanting to be pedantic but the term 4V and 2V appears to be some what mis-used. When you say that most engines are 2V, don't you actually mean 4V with small port heads? In other words, the term 4V and 2V stands for 4 venturi and 2 venturi.
As with all XC/D/E V8 cars, they were all 4V cars with small port heads. All of the XW/Y/A and early XB GT's had tyhe 4V motors but with the big port heads. Yes??
Not wanting to be pedantic but the term 4V and 2V appears to be some what mis-used. When you say that most engines are 2V, don't you actually mean 4V with small port heads? In other words, the term 4V and 2V stands for 4 venturi and 2 venturi.
As with all XC/D/E V8 cars, they were all 4V cars with small port heads. All of the XW/Y/A and early XB GT's had tyhe 4V motors but with the big port heads. Yes??
i'd suggest it's quite well known that large port heads are said to be 4v and small port are 2v regardless of ventury (in australia of course) the yanks never had 2v closed chamber heads. this is a good thing because we have so many for ourselves
i believe with a little bit of porting our 2v closed chamber heads are the best for "street" engines
Just kididing around clevo400. But back to the 2v and 4v. I think if we left it as most people understand, 2v and 4v are small/big ports, 2 barrel and 4 barrrel are the number of venturies. Savy.
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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.
On late model (XC-on) Clevos, CLosed chambers were used on 302s to give a compression ratio of 9.2:1 and open chamber (referred to as pollution heads in the USA) were used on 351s to give a comp. ratio of 8.9:1. Bolt 302 heads onto a 351 to give 11:1 comp. You will need LPG or high octane petrol to get them to run unless you open out the cambers a bit. All late model aussie heads were (2V small port). All ran Carter Thermoquad 4Venturi caburettors.
Running a 351, with 58cc closed chamber heads, and the standard deck height of cleveland block of approx 30 thou, you would have about 10.3:1. As long as the deck has not been machined down, you be able to run pump fuel fine. I have many mates with closed chamber heads on 351's using pump fuel, and they dont ping. The other cosideration is the cam. If you run a very small or standard cam, the dynamic compression will be higher and may casue a bit of pinging. If you are running a decent cam with perfrmance in mind, it would be ok. Again, why would one want run high compression, with a standard cam if they didnt have performance in mind.
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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.
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Re: Open/Closed heads
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