7.4 roller rocker arms

[ericcarr2000]

I have a 1990 7.4 motor in which I'd like to install a set of roller rocker arms. Can anyone tell me what size I beed?

 

[NHGuy]

You need to figure out what heads you have and get rockers for them. Find out how to ID them through Chevy reference material. Boat stuff can run a few years later than auto & light truck so don't get locked inn by product year. Just get casting numbers and whatever other idetifiers are needed by your rocker supplier, I'd try Summit Racing, Comp Cams, Hotrodders forum, Speedway motors. Once you have done some reading it will start to clear up.
Watch out for rockers that require tall valve covers, if they are needed make sure they will allow your exhaust to clear the covers.

 

[Bondo]

Ayuh,.... Unless there's an actual problem, yer just throwin' money away,....

 

[alldodge]

+1^ Or unless your planning on building a lot of power out of your motor

 

[ericcarr2000]

No the thing is roller rocker arms really don't have the amount of friction that the standard tipped rocker arms do. I'm just partial to trying to reduce the amount of friction.

 

[Scott Danforth]

summit makes a great inexpensive stamped roller tipped rocker for the BBC and SBC motors. however other than the $110 lighter wallet, you wont notice the difference unless you start getting into the internals of the motor.

 

[gm280]

No the thing is roller rocker arms really don't have the amount of friction that the standard tipped rocker arms do. I'm just partial to trying to reduce the amount of friction.

If that IS your reason or goal, then why not change to roller cam and lifters as well. I am sure changing to roller rockers will never be seen as any real improvement that you will notice or could even measure. The miniscule difference is not something you will feel running. Usually when somebody goes that route, they are doing everything else inside as well. Then you can have a more balanced package that complements each other... In fact having the engine balanced would gain more power then simply changing roller rockers. Been there and done that! JMHO!

Not knowing what you presently have, if you want more noticeable HP, fit it with some quality headers. That is the only one "bolt on" option that I ever actually felt an improvement with building engines in my days. Of course a total rebuilt reasonable package inside and out will yield a better HP option...

 

[ericcarr2000]

Hmm.... Never thought about headers. Where Can I buy a set of them, and will they bolt right up to everything?

 

[alldodge]

Hmm.... Never thought about headers. Where Can I buy a set of them, and will they bolt right up to everything?

Search for marine performance exhaust and names such as GIL, Eddie Marine, IMCO, Stainless Marin and others. You can really lighten your wallet quick getting into performance parts. The low end side can run you EMI thunder for 2K all the way up to 10K for E-tops and system components. Exp: with EMI thunder exhaust you may also need the alternator and fuel filter kit to move them out of the way of the header.
http://eddiemarine.com/emi-thunder-exhaust/emi-thunder-exhaust-big-block-chevy

http://teaguecustommarine.com/em0011/454-502-e-top-platinum-kit.html

 

[ericcarr2000]

Holly Molly..... I'll pass this time around. Why in the hell are these so much more than a pair of street headers?

 

[Scott Danforth]

Holly Molly..... I'll pass this time around. Why in the hell are these so much more than a pair of street headers?

because any yahoo can make a set of street rod headers for $100 out of mild steel tubing in high volume and the general public pays $400 for them. marine headers are made from 316L stainless and are double walled to be water jacketed, and made in small batches (like 1-10 at a time), mostly by craftsmen. The material alone is probably $200, however there is about $800 in labor. Then you have the overhead, SG&A, and warranty accrual, so the general public pays $2k +

Additionally - If a street rod header breaks, you as mr street rod owner are just mildly annoyed, call the company and get another set - so the quality is not needed and the price is low. if a set of marine headers fail, you mr boat owner have just trashed your motor. so there is a bit more quality that goes into them and the price is much higher.

 

[NHGuy]

Your original thought of reducing friction with full roller rockers is supposed to be good for 10 hp. I don't think you'd feel it without a cam, you could do a lot with a cam and good heads. Even more with proper pistons for the heads and a carefully selected combustion ratio. Only thing is, then you are spending much more money.
Performance costs money. The problem is, how fast do you want to go?