Vintage Mustang Forums banner
1 - 12 of 12 Posts

·
Registered
Joined
·
912 Posts
Discussion Starter · #1 ·
I'm looking for more power out of my 2v 351c and it seems that starting at the heads is the way to go about it. What kind of differences would be noticed between my 2v heads and open or closed chamber 4v heads. What are quench chamber heads? Getting a new intake really won't be a big deal to me so don't worry about that. What happens to the power band, throttle response, what is the change in output etc.

Also, what is the normal operating oil pressure for my 351c? Right now if it is at idle the psi is around 40, I give it gas and it stays between 55-75. Is this good or bad?
 

·
Registered
Joined
·
10,588 Posts
Unless I hear something with the word racing in it, I'd recommend staying with the 2V heads. What vehicle is this in? Your handle doesn't provide any clues.

What are quench chamber heads?

Closed chamber. Those are the typically more desired of the 335 series 4V heads. 289/302/351 (early versions) heads are quench chamber as well. Fast combusting but not always the best for smog emissions.

What happens to the power band, throttle response, what is the change in output etc.

Everything moves higher, hence the need to include the word racing *G*

Also, what is the normal operating oil pressure for my 351c? Right now if it is at idle the psi is around 40, I give it gas and it stays between 55-75. Is this good or bad?

IMO, pretty darned good.......I've seen typical operating pressures at half that in some stockers.
 
G

·
Leave the heads alone. Get a good 650cfm carb, aftermarket intake, headers, and a Petronix ignigion module. Tune the carb if you know how or have it professionally done.

Total investment about $800.00. Money well spent.
 

·
Registered
Joined
·
912 Posts
Discussion Starter · #5 ·
It has a good 750 cfm carb, a mean cam, and I mean this thing will rattle your teeth out at a stop light, Edelbrock Performer 4bbl intake, tri-ys and straight pipes already.

Where can I go from there without having to change around pistons and such? I'm thinking of roller rockers to replace the stock rocker arms, what will that do for me? This car will never be a daily driver, it's purely for my own enjoyment. Probobly will not see track time either. BTW, the stall converter on this thing seems WAY to high for the engine. I believe there are some miss-matched parts in this thing, for instance the angry cam and an intake that makes its power from 0-5500 rpm. How difficult is it to replace a stall converter?
 

·
Registered
Joined
·
912 Posts
Discussion Starter · #6 ·
Forgot to mention, this is in my 1970 Mach 1. It also has a Unilite dizzy and an Accel coil, I forget its name. Most of the engine work was done by the PO.
 

·
Registered
Joined
·
4,971 Posts
If you really want more performance, ie. more HP, try the 4V closed/quench chamber heads. Understand that these heads will increase your compression ratio to the upper limits for pump gas. I always find it interesting that the myriad of new cylinder head manufacturers use the stock 2V head when comparing air flow numbers, etc. Sometimes these manufacturers will obscurely mention the stock 4V head as a "Race Only" head, but rarely will they publish bench flow numbers comparing their $1000 plus aluminum heads that they want you to buy to the stock flow numbers of the 4V. The 4V actually flows TOO MUCH air, thus the advent of "restrictor plates". The 4V was used successfully used on the BOSS 302 engine. When the engine is built around the 4V heads, the 4V heads are outstanding. Simply taking off a set of 2V heads and bolting on a set of 4V heads may create other engine anomalies to occur, like tuning. I swear by the 4V head, but I also don't mind spending $75 on a half tank of racing fuel.
 

·
Registered
Joined
·
1,113 Posts
Well, you may consider looking into a Weiand X-celerator intake for 2V heads... since there is no Performer RPM type manifold for the Cleveland 2V at this time. Normally, I would tend to stick to a dual-plane intake but a lot of people at the Cleveland Forum seem to think the Weiand gives up very little down low & has good gains in the mid & upper RPM's.

Also, there is one other head with quench chambers, the Aussie head used on their 302C motors. These have 2V port sizes, so you don't need to swap headers. Of course, if you swap heads, the investment begins to rise...

Doug
 

·
Registered
Joined
·
10,588 Posts
Sounds like you got some good diverse advice from others....

Given the vehicle, personally I'd stick with the heads you've got or possibly go to the Aussie heads.

I've never seen a 335 in a doorslammer which had too much converter. Most of my racing buddies ran 8" converters at the track (about 5K rpm flash speed) and 10" units on the street (3.2K rpm flash speed). The heavier the vehicle, the higher the flash speed.
 
1 - 12 of 12 Posts
Top