I have heard good things about both of these units. I have not heard anything bad about the Rochester but have heard that the Holley has "issues" with injectors leaking. On the other side of the coin, the cheapest new Rochester 454 I have found is over 600 smackers while the Holley is 299.99. Why the price difference? Is the Rochester that much better? Also, are they both a staight bolt ons when replacing a 305 throttle body? Thanks, TBI'ers.

 

they will bolt to stock intakes but the bores are bigger those the mentioned units. The wiring is slightly different but nothing major.

GM injectors seem to handle a wider range of pressure along with giving a better spray pattern than the Chrysler type(that holley uses). Other than the injectors I doubt there is any real differeance. A popular notion is to use the GM injector pod on the holley unit.

------------------
-Tas
'89 Formula WS-6
[soon to be Torch Red with black hood and headlights =) ]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz | ICQ 82881207

[This message has been edited by Tas (edited February 27, 2001).]

 

The castings are essentially the same. I assumed that holley had bought the molds etc. from rochester. As it turns out i talked to somebody who had a friend who worked for holley until about 16 years ago. GM had holley design it, then stolethe design, there was legal battles etc.. guess which giant won.

Thats how i heard it. (but hearsay doesnt stand up in court does it . )

So, holleys is essentially the same as the rochester because holley designed em both.

 

btw, a lot of holleys supposed flow increase is from the smaller less obtrusive injectors.They must have figured carefully the tradeoff of using them. They knew that people would buy it if it FLOWED MORE AIR etc..., but if it flowed the same amount of air, and used gm injectors, (which could be not holleys design, the pod i mean) that they wouldnt sell as many because then it would be stock.

 

Thats how i heard it. (but hearsay doesnt stand up in court does it . )


Yeah, I learned about that topic in the o.j. simpson trial. Also that if the throttle body doesn't fit, you must aquit.

Thanks for the valuable info.

 

I'm looking at changing from a Rochester 4 barrel to a Holley 670cfm. I know that because the Rochester uses a spread bore and the Holley is a square bore, an adapter plate needs to be used. I heard once a long time ago that the Rochester 4bbl was better than a Holley 670. But I've only heard that once, and I'm pretty sure a brand new carb would perform better than one thats 30 years old, like the one in my 84 camaro. Does anybody know which I'd be better off with?

 

they are talking about throttle bodies not carburetors.

carburetor wise i prefer holley over rochester or edelbrock.

if you have carb question you should ask under carburetor section on site.