Wills and Black dog,

Thanks for your input. Certainly it isnt late as this is something I am just preparing for in advance. I wanted to get the question out there early as Ive a feeling its going to take me a fair while to make a desicion on this.

Interesting point about the Torker. I would say that 99% of what I have read suggests that a single plane would not be suitable for my requirements. However I have read a few posts by users of Single planes that seem perfectly happy with thiers for street use. Equally, using the ZZ383 for an example (and if I recall correctly) I believe GM used a single plane for the figures they quote on this motor and that seems to have a fair spead of power.

Yes.. I have noted the performers (non RPM) to be a popular option. In fact I feel maybe I am being a little to finickity about the whole issue. Indeed if I use the ZZ383 as an example again I note that they lose 15-20HP using a low rise intake. This got me thinking of an admittedly stupid sounding point, which is.

My usual manner of driving has not historically been to use very high revs. I presume that with a stronger motor I am still unlikely (maybe even less likely) to use high revs. So (and here comes the stupid bit). If I were to use a low rise intake, but convince myself to use say an extra 500RPM than I would have before, then I would essentially 'retreive' the lost HP that I may have noticed using the high rise. :o .. yes.. a weird proposition.. but there is, I hope, some logic in my thought. I suppose the trick here is that I wouldnt ultimately drive any different, but if I convinced myself that the scenario were true I'd at least know that I "could" retreive the HP if I wanted (if you dont understand what I mean, dont worry, I have daft thoughts sometimes, but just to be clear... I am not saying that I would actually increase the potential of the engine by revving harder, just saying that I could USE more of the power available by driving differently).

Anyway, contrary to the above, I am still tempted to try a high rise (e.g. RPM) with a shorter carb, like a demon, given that somehow, several people seem to have got this to work. Worse case is that I would have to sell the intake on, but if I could retreive 70 - 80% of the cost, then it may be worth it to see if I could have my intake of choice. (I should note here that one of my many reasons for asking this oft asked question is because in other threads - on occassion - there seems to be confusion whether people are actually using RPMs or not, and there seems a small possibility that people have responded saying they have fit "one of these" but maybe have non RPM air-gaps for example. Im not saying this is the case, or people dont know what they have got.. just that there seems to be this possiblity.

Finally, if you are still here.. could I ask does anyone know the dimensions (height) of the stock intake - either pad height OR A-B. I have looked at mine but cant really get a good measurement with the carby on. Obviously if the need arises I will remove it (and if it helps, post the measurements) but if someone already knows it would be most helpful.

 

I did not measure the height of a given manifold, but here are the pictures I took showing the differences in a few intakes. Using the Edelbrock Performer RPM as the highest standard, the other three intakes are shown with the measurements of how much they are shorter than the RPM. The RPM is not an air gap, but the performer on the right is an air gap. all but the RPM are spreadbore bases.

 

I just installed the edelbrock 2710 on my stock block 350 with older double hump heads
and the 256 comp cam . Tight fit , butI'll make it fit with drop base .

 

Off topic, but I'm curious how you can tell from the pictures without being able to see the casting number? What tips it off? It does look alot like the 3972110 intake I had.

 

Look at the flange where port runners meet the cylinder heads, Z/28 LT-1 intakes had thin area above top of intake runners. Sometimes that thin area can cause intake leaks, the GM performance intake in the photo is very simular to LT-1 in runner shape but, so is a Holley 300-36 dual plane intake (also cast at the Winters foundry.)

It is very hard to enlarge ports of a facotry LT-1 intake to the small race port size commonly known as a Fel-Pro #1205 intake size because of the thin roof of the runner casting.

FYI in dyno testing my 355 LT-1 motor and Edelbrock RPM intake made a whopping 4HP more than a factory high rise on a 425HP solid roller motor with decent heads. Victor JR went another 19HP better but lost about 1000RPM of decent torque on the bottom end RPM range. Testing was done before RPM Air-Gap was avalible so no data for it. I would suspect Air-Gap intake would be up 10-14HP on a GM dual plane intake with decent bottom end.

 

C69vette,

Great pics. Very informative.. thanks.

msandym,

Please dont take this the wrong way, as I am certainly greateful for your input and taking the time to assist.. but it is these scenarios, such as that you have detailed, that leave me a little confused..

that is to say that the performer, as far as I am aware, should fit... yet I have read posts, like yours, that not only have pointed out that it is tight, but also implied that they have had to 'fettle' to get them in, in the same manner that those with RPM's have commented, even thoug the RPM's are much bigger.

Im beggining to think that the tolerances on the bodywork / maybe engine mount points etc must be a contributive factor.

 

CairnsFella,
thanks for taking my ideas into account and yes i fully understand your logic behind the extra 500 rpm thing! Good luck in finding the intake that best suits your need!

Will

 

I just replaced my torker II with the edelbrock 2701 dual plane . I have the original 350 block with double hump heads . It's real tight , but with a drop base air cleaner , it should fit . I'm going to use a 14" circle of plexiglass with a 3/8 " mounting hole in the middle for a flat , clear top . I had to cut down the threaded rod on the carb , but It will fit .
I also changed the cam , runs real good . I like the look of the stock hood too .
Good luck !

 

msandym,

This is another one of those posts that have me scratching my head. Your experience suggests that the 2701 is only JUST going to fit.... so how the heck does anyone fit the taller RPM's in.

I am interested by your custom cleaner cover... I did wonder if anyone had tried any fabrication to solve the problem.

 

I'm just relating my experience with these two manifolds . The torker fit with no problem , but I wanted some more low end . I bought the 2701 , Its on the car now . The problem with the air cleaner is the top , its not flat , it has a slight rise to it that they all seem to have . I got the idea of the flat plexi from someone on the forum that made something similar . I didn't mean to mislead , but this is based only my experience with these two manifolds

 

Maybe we're just getting into semantics here, as you are right, that manifold did not come from the factory on any Chevrolet cars. But if you refer to the Chevrolet Power Catalog, 6th Edition, page 5-55 you will see that Chevrolet does indeed refer to that manifold as "Chevrolet high-rise aluminum intake manifold #14044836 was original equipment on early Z28 and LT1 small-blocks."

Cheers,
Pete

 

CairnsFella,
Welcome to Oz! I'm in Melbourne but I have a brother up in PD, he's turning 60 in August and I hope to be up there for a week or so, maybe we could catch up for a cold one during my visit.

I met Solid LT1 during a holiday in the US last August and he's a member of a local Corvette Club; they're a nice bunch of blokes. I even bought a car from him sight unseen, and it was exactly as he described it when it arrived in March this year. Well, apart from some body damage that happened during its transfer to Oz. Not Solid's fault.

He knows what he's talking about when it comes to engines and I would suggest that you seriously consider the manifold he offered you. Freight to Australia will probably cost about $100, unless you can get it into a container bringing in cars etc. Try to buy a new US built manifold at one of the big speed retailers in Oz and his price, even with the postage, is a good deal.

I bought an Edelbrock RPM Air Gap for my other Corvette, and when I go to fit it, I will post photos of what AC does and does not fit. I expect to have to fabricate an AC to make it fit under a stock '74 hood. The car came without an original Cowl Induction AC, so I won't be cutting up anything original.

Keep us posted and give me a call if you need any more advice.
03 9502 3227.

Regards from Down Under

aussiejohn

 

Msandmym...
sorry... didnt mean to sound like I had issue with your comment... of course I asked my question to find out peoples experiences. I was just trying to use your comment as an example of many similar comments I have read that seem a little at odds with a similar number of others findings with larger manifolds. I am not trying to say one group is wrong (or indeed either), but just how hard it is to pin this issue down, without ultimately trying it for myself.

Aussie John,

Thank mate, and Im grateful for your support of Solids 'solid' reputation. However, as you may or may not have noted, this question was raised as pre-emptive research. I am yet to even have a motor onto which the manifold would be going, so I would be a little remiss in making a purchase just yet, no matter how much of a bargain.

Thanks for the input though.. appreciatted.

At the speed things are (arent) going.. I'll be supprised if I have my car back on the road before August though even with the existing motor.

 

CairnsFella,
I want to say thank you for actually getting "your answer" out of this question.. most people dont have the gall to just out right say that people have not answered their question any more. and when the question is asked again, peoples ego's get hurt. I cant contribute any personal knowledge on this subject, just the well wishes in your fact finding quest. Good luck!
Josh

 

So I'm in a similar boat here. I got a performer RPM intake cheap from a friend of mine, now I'm trying to figure out which carb to put on it. After putting it on the car and taking measurements, I've lost 2 1/2 inches of clearance. I'd like to get the edelbrock performer carburetor because the price is reasonable, but can't find any height measurements and I'm thinking it might be too tall. The speed demon carburetor is only 4 1/2 inches tall so that might be the way to go....Let us know what you end up doing...

 

Joshtried,

Thanks for the support mate.. I hope I havent come over as a bully, or pushy. The reality is more that Im just plain dumb, and need a little extra clarity than perhaps works for others. But I must extend my thanks to everyone who has taken time to contribute.

Atarii
2 1/2 inches is a big loss to make back! Unless having a short cleaner can help (which would be suprised iof it could help THAT much, then a shorter carb sounds like the only option. I think its more a case that I will be looking to hear how you go. Any activity I understake will be sometime off, but I wanted to get as clear as possible on this in advance, as I know if I waited till I started, I would have been frustrated with the holdup whilst I looked into the problem.