these heads will be going onto a 383 stroker i just want to make sure they flow good for 7000 rpm's http://www.pawengineparts.com/shoppi...6890&catid=992

 

RHS is a good company however on a 383 you will want a 200cc in. runner they did not mention what size runner these are. I would use a Brodix IK 200 which flows 265 cfm @ .550 lift which would make power up to 6500 RPM which works perfect with hyd. flat or hyd. roller cams. If you want more RPM like 7000 RPM you will need aprox. 290 - 300 cfm to acheive this on a 383 depending on your cam choice as well. Good luck

 

For a 383 to make peak power around 7000 RPM, the choke point of the intake port has to be around 2.2 square inches of cross-section. Heads with this size port usually have 220 cc intake ports or larger.

Being that the link to those RHS heads does not give the intake port volume or the choke point size, I doubt they will do the job.

If all you want is to be able to rev to 7000 RPM, any head including stock will do that. You just won't make much power up there.

 

im really dont grasp heads to much at all i dont completely understand everything those are just some heads i had access to for 200$ lol so can u give me a brand of head that handles 275-300cfm i mean if you what one is just link it or message me i have 2.77 gear rear end and i really dont wunna change em out i just want to get heads good for 7000 rpm cause thats how the engine was built was to peak at 7000 and a nice stall converter for now i through 305 heads on it to bump compression and its working like a friggin charm its a running mother trucker just runs out of air at 5500 rpm lol

 

Need more combination info. I will say this when you move your RPM band up you also lose low end power depending on your camshaft specs. So if you want good power in the lower RPM zone you will certainly want to move the rear gear ratio up as well. What is your comp. ratio, camshaft specs., trans, converter, rear tire dia. ? And what is the car used for cruising, drag race, road race?

 

Wow, that would be quite the combination mismatch.
I'm not against keeping the 2.77 gearing, but spec'ing heads for 7000 RPM power would be a big mistake when running an automatic with highway gears on the street.
I'm going to suggest that you aquire and build the RHS heads, or build your 305 heads, as in the info in my signature links.

It sounds to me like you were originally asking about the ability to rev to 7000 RPM. Running out of breath or not is sort of a side issue, as you're most likely outpacing the ability of your valvetrain to control the valves. A valvetrain upgrade is in order. Also, if your 305 heads are unported and have the stock sized valves, then you are indeed running out of breath early. Your heads would need major porting and an increase in valve size along with the valvetrain upgrade.

You will need a valve, retainer, and spring combination that is relatively light in weight for the amount of spring pressure. Comp Cams 918 springs are a great choice there.

You will also need a quality lifter set that can function properly up to 7000 RPM. Comp Cams retro-fit hydraulic rollers will do this.

The RHS heads would require much less work to reach your goal.

 

i have chosen manley double spring spring manley valve retainers but have not bought valves the heads are stock unported i run out of breath extremely fast. i do not plan on keeping the 305 for stroking a motor is to take in more air/gas and 305 heads defeat that purpose in my opinion porting 305 heads to a decent valve size is mega expensive for a shop to do they quoted me at 325$. my compression is 12.3:1 i run mixed gas. i have nooooo stall turbo 350 trans my tires are 235/70/r15 used for strip street occasionally road race

 

What camshaft hyd. flat, hyd. roller, solid flat, solid roller? and what is the duration @.050 , lobe seperation angle and lift? And do you have 12.3:1 with 305 heads? If you are not sure, what is the bore size , the piston volume and the deck height. You should be able to get this info. from the shop that performed your work. Also what type of intake manifold are you using and are you EFI or carb.

 

yes the compression ratio was 12.3 to 1 thats mesuring deck bore gasket thickness head chamber everything with the 305 heads. ill the camshaft was from comp cams the link is

http://www.compcams.com/Cam_Specs/Ca...?csid=109&sb=2

carb

 

Giant cam. You're going to need some Dart Pro1 220's or better.
-and a really good stall.

 

Since the cam is a hyd. flat I would try to have the combination make all of it's power by 6500 rpm because valve float is inevitable @ 7,000 because hyd. flats should only have 115# on the seat and 315# open. And since your lift is only .500 most heads that are capable of 300 + cfm don't flow near 300 until .600 lift so a perfect choice would be the Brodix IK 200 they flow 260 cfm @ .500 which would give you 6,300 rpm with a well matched in. manifold such as performer rpm air gap. We have built several of these combos with less duration than you have and 10.5:1 compression in 3,300 lb. cars running 10.90 @ 121.0 mph on pump gas n/a. It's all about the combination. That means gear ratio, convertor, suspension, and of course well matched engine parts.

 

little expensive in my opinion lol any knock offs thats are just as good?

 

Pro Topline,
or Renegade has a 210cc aluminum bare casting for $210 each.