Vortec Intake

[FreeBeeTony]

Starting to narrow down my search for parts.......<br /><br />Think I am going to go for the GM High rise instead of the Edelbrock .....<br /><br />Any thoughts on my decision?

 

[John_S]

Re: Vortec Intake

I would think the Edelbrock Performer and Performer RPM, have a proven track record. What is driving your decission to the GM and higher price tag? just wondering.

 

[FreeBeeTony]

Re: Vortec Intake

I had the GM high rise originally.........guess I just really like the thought of the high rise and keeping it GM.<br /><br />I read in Dennis MOore's book that the best intake manifold for the non-vortec was the high rise........thought it might also apply to this situation.

 

[John_S]

Re: Vortec Intake

The GM highrise is highly rated on the older style heads. The Edelbrocks have been available for vortec heads, even back when Moore wrote the book. Don't think the GM was available, then. Anyway, I have read allot of posts about upgrading to vortec heads, and the most common intake used is the Edelbrock. Here is an article on upgrading 2 to 4brl, using the performer : article I have not seen a post about anyone using that particular GM one. Not saying it is a "bad" one. Probably couldn't tell the difference, unless on a dyno. This is probably one time, I wouldn't pay more money for the GM, but JMHO.

 

[FreeBeeTony]

Re: Vortec Intake

Any other opinions?<br /><br />For some reason.....I am still leaning towards the high rise.

 

[Buttanic]

Re: Vortec Intake

In a lot of cases the the GM performance parts are made for GM by the performance aftermarket suppliers. I believe the aluminum hi rise on the 1970 HP 350 was made by Holly. The performer is a good manifold at a good price, I wouldn't hesitate to use it.

 

[John_S]

Re: Vortec Intake

I imagine Edelbrocks vortec manifolds are similiar to the ones they have for the pre-vortec heads. The Performer RPM was the high-rise version, that is essentially equivelent to the cast-iron high-rise you have. The performer, is about in the middle between the standard 4brl and the high-rise. I believe I remember reading you have a boat on the heavier side. The slight improvement in low rpm performance vs top-end, might be of more use to you. Either one, you should end up with around 300hp. <br /><br />BTW, what is the condition of your cast-iron intake? Someone, like me, with pre-vortec heads, might want to know.

 

[FreeBeeTony]

Re: Vortec Intake

The boat is a 24' Grady White.....~4000# w/ engine.<br /><br />I am assuming the high rise would help the low end some........I am looking to stay at a relatively low RPM and be able to turn a biger prop.<br /><br />The original manifold is in nice shape......I might be looking to part with the heads, manifold and carb when all is said and done and the boat is running right next spring.<br /><br />Where in NY are you John?

 

[John_S]

Re: Vortec Intake

Tony,<br /><br />Home is 30 minutes outside Binghamton, boat resides in the lower adirondaks. I would not be interested in the heads. Is the carb a Q-jet or Weber 750?

 

[FreeBeeTony]

Re: Vortec Intake

Weber 650.<br /><br />Not going to part with anything until the test run in the spring.<br /><br />What are you running now?

 

[John_S]

Re: Vortec Intake

Other 350 Mags from mid 90's, I've seen, had the 750cfm weber. What is the part number on the carb? or if you have the carb off the manifold, if the primary bores are slightly smaller than the secondaries, its a 600/625 cfm. If all the same, it is a 750 cfm. <br /><br />Completely stock, 1997 5.7L 2-barrel, pre-vortec, 210hp, in a 20' bowrider. I have a new edelbrock performer intake to install, but the cast iron high rise does intrest me at the right price! Have a K&N flame arrestor, but won't buy carb till next spring when I install. Will either be an edelbrock 600, or possibly a rebuilt Q-jet. Even though I worry about getting the Q-jet adjusted, it does seem to be the recommended carb for extending idle/low speed, and stop n go (tubing/skiing) that are the primary uses of our boat.<br /><br />When my engine needs to be rebuilt or new-long block, would probably go to vortec heads, like you, then. With my flat top pistons, compression is too high for my conservative tastes.

 

[FreeBeeTony]

Re: Vortec Intake

I'm pretty sure it's the 600/625.<br /><br />At the hieght of my frustration this summer in troubleshooting my problem, I bought a new 1409 Edelbrock........obviously had no effect......other than making me ~$300 poorer!<br /><br />The original Weber/Carter AFB has been rebuilt/cleaned (twice)!<br /><br />Probably going to order the manifold (GM high rise) today.<br /><br />Hope to put the engine back in this w/e and install the heads and manifold next w/e.

 

[ron7000]

Re: Vortec Intake

if you tile the pictures of the gm vs edelbrock manifold in photoeditor or similar program, you'll notice the gm manifold is a square bore vs the edelbrock being a spread bore I believe.<br />I'm not familiar with weber carbs, you said you have a weber 650 currently? If its spreadbore, then you'll need to go with the edelbrock manifold. If you go with the gm manifold and the picture is correct for your application, you'll need an adapter plate so the secondary throttle blades can open. Are edelbrock carbs weber carbs, or basically the same design? If so, I would think ideally you'd want a matched set- edlebrock manifold with edelbrock/weber carb with no adapter plate or spacer. Now if you go with the gm manifold and get a nice holley carb, then that sounds like a good setup too (I like holleys).

 

[FreeBeeTony]

Re: Vortec Intake

Ron, I think you might be confused........the Weber/Carter is the Square bore design, the Holley (some I think) is the spread bore design. I contacted Summit and they said the GM would accept to Edelbrock square bore.........

 

[John_S]

Re: Vortec Intake

The 1409 is a 600/625 cfm, square bore carb. edelbrock says 600, weber say 625. Regardless of the number, they are both the same. If you get a chance, look at your original carb for number/size. I'd be surprised if it is not a 750 cfm. My merc manual, which covers your year engine, only shows 750s on the 350 mag. <br /><br />The Edelbrock performer can mount a spread bore or a square bore carb. The GM shown, is for square bore only. The performer-rpm, for vortec heads, I think is square bore only, but i didn't go recheck that. <br /><br />Holly makes primarily square bore carbs, but do make some spread bore, Q-jet replacements.

 

[FreeBeeTony]

Re: Vortec Intake

If it was a 750 cfm..........I think that would be too big for the 350 anyway...

 

[vettman]

Re: Vortec Intake

John_s<br /> According to Jegs magazine your right. Squarebore only for Vortec heads. Probably could get an adapter to use a sreadbore.

 

[John_S]

Re: Vortec Intake

Tony,<br />Theoreticly, more cfm than a relatively stock 350 could handle. 750cfm Q-jets, were used on many a small block. The secondaries are vacuum controlled, and open as your engine needs. On a stock small block, they will not be open all the way, at boat rpms (5K max). The 1409 and 1410 edelbrocks have vacuum secodaries, as well. The 1409, with different jets, works on the 6 cylinder. More carb that it could possibly handle, too. If they were mechanical secondaries, they would be pigs! Anyway, nothing wrong with the 600/625. Isn't it a hotrod tradition, when going with a high-rise, having an oversize carb? I still think the mid-rise with 600/625 is a better match for your app, but maybe you are a WOT type of guy. <br /><br /><br />vettman,<br />Thanks for confirming, I don't have too bad of a memory, yet... <br />I wouldn't use an adapter, because of air flow restrictions, and lost performance. If you read Dennis Moore's book, you get the feeling that it really pi$$ed him off, that mercruiser used an adapter on many of its stock 4brl manifolds, when Q-jets went out of production, and replaced by the square bore webers.

 

[Bondo]

Re: Vortec Intake

Originally posted by FreeBeeTony:<br /> Starting to narrow down my search for parts.......<br /><br />Think I am going to go for the GM High rise instead of the Edelbrock .....<br /><br />Any thoughts on my decision?

I'd be Happy with Either 1 of them,............ <br /><br />What are the Extra plugable ports about mid-way on the GM manifold,.???<br /><br />I believe that your Carb.s will fit either of them,......<br />The small Carter Clones are a Square Bore carb.,...... That Looks like a Spread Bore.......

 

[vettman]

Re: Vortec Intake

Hey John_s;<br /> <br /> Who's Dennis Moore, and where's his info available? I've got that article from boating magazine you mentioned and will do the same to my 5.0 Vortec that is now a 2 barrel. Volvo was kind enough to sit my -2- on a 4 barrel high rise. Going with the holley 600 marine. Manifold is Performer RPM with VOLVO name.