Hi guys.

Please please do not flame me here.. I have researched this question, but am yet to find an answer that is anywhere near definitive (perhaps because there is no such answer ???).

Anyway. I have a 327/350 1968 convertible, and I have been planning for many years to replace the tired old motor. Although there are still many outstanding questions re: how I actually come by the motor (crate / small block build up / scratch build etc), my question here solely concerns the intake manifold.

The new motor will still be a small block (along the lines of a 383 or 400), but in my ongoing research I have noticed that there are clearance issues with many performance intake manifolds that most people are unable to resolve.

It is my understanding that items such as the performer or performer air gap (non RPM) fit under the stock hood, as does the weiand stealth and action plus (some of these possibly requiring drop base cleaners).

Some people state that they have installed RPM's with drop bases, although I have read equally of people not being able to do the same.

My build has, I believe, only moderate rather than high performance requirements, wanting a genuine 400 to 450 horse, but I am able to find little on the above "fitting" manifolds to suggest that they wont be a restriction in the chain. Indeed I have seen builds of similar size only just making these figures with RPM manifolds.

So.. if you are still here , to the actual questions. Of which there are a few.

• I have read many forums noting this problem, but few that are very recent, so firstly is there any new items that would solve my conundrum?
  
• Second. As noted, even the items listed as suitable above "may" require a drop base manifold. But I have read also that even if you have say a 3" cleaner, these are still more restrictive than a 3" on a standard base. Is this true.
  
• Very few of the articles I read mention the height of the carb. I assume they do vary in height, even if only marginally. Is this the case... are there any recommended carbs to consider given the requirements I have listed (see also following question)?
  
• Some people have mentioned filing down parts of the carb for clearance or to accomodate the drop base filter. I am rather a novice when it comes to carbs, but given that I would be getting a new carb, and assuming for a moment a drop base is required, would there not be carbs that are suitable for my requirements as they come, and how do I know what is ok and what isnt?

As I say, I have looked into this, and I suppose it is looking like a performer, stealth or action plus will have to be the go, but I am fearing that I should tone down other component considerations in line with the capabilities of these manifolds.

I should also explain that I am located in Australia (having moved here from England and bringing my vette with me ) so supplies are scarce here and I will likely need to order from the U.S. so I want to make sure I am doing the right thing before I buy.

Thanks for your tolerance on this age old question.

(Edit)
Damn.... Ive been looking into this for aaaaages.. but no sooner do I post than I find some more recent threads. However these still seem to be a little non conclusive, with posts simply stating "weiand stealth" and thats it?, or RPM air gap, can be made to fit.. (but how??), so, given that I have also asked some carb questions, I hope its ok if my post remains, and please feel free to ignore me if you feel there is nothing to add).

 

A few options:

Change the hood to big block or even the higher L88. That will set you back about a grand or more landed in Aust. I got an L88 about a year ago to Darwin.

It MAY be possible to keep the stock hood if you select a Holley style carb without a choke tower (you wont need a choke in the tropics), select the lowest performance dual plane (might be a Wieand Stealth, not sure) select a 3" drop down but use a 2.5" filter. That will put the lid close to the carb and obviously hurt airflow but might fit.

Another option would be to use the low rise single plane Edelbrock Torker and fit a throttle body injection system. That will fit, run well at low and higher rpm but will be more expensive.

 

Simmo,

Thanks for your response.

First off, and I probably should have said before, I really want to keep the stock hood (yes... I want to have my cake and eat it.... whatever that old proverb really means !!)

As I mentioned, Im no carb expert... do listings say. "no choke tower" ? or else how do I tell.

Is the damage to the airflow you mention and the low performance dual plane going to prevent me reaching my targets ?

Looked at the TBI systems. Yes, that probably is a little too expensive for me. I wont write it off though, but would certainly prefer to stay with a conventional carby. (though I though the torker was more a mid / high rev intake.. I dodnt mention but I would prefer low to mid performance.

Sorry if I sound contrary there.. more a case of your answers have highlighted points I failed to initally clarify

 

If you use the Torker with a carb, low end response might not be all that good but injection will improve that. Another option would be to go for the most cubic inches using the 400 or 350 block (somewhere between 396-415 cui), use a high flowing but small runner head (say afr180cc) then the torker with a 750 vac sec carb with annular booster and no choke tower like a mighty demon. That will run well at most revs.

Hold everything there is another manifold but its discontinued and only available SH on ebay. A Wieand street ram. its single plane, lowish rise, good runner shape, small runners and small phlenum. Works a treat. I put one on a friends HT Premier with a 383 and powerglide and the 750 demon. No flat spots, it pulls hard from 2000rpm. If you weld in runner extensions it goes even better. Will still need the drop down airfilter base. Definately worth trying this one, better than the Torker.

You havent said if you have an auto or manual, if the manual is close or wide ratio and what you diff ratio is. You may need a 2200 stall converter with an auto and tallish gears.

 

I'll have a look into the "street ram" you mention.

The idea of maximising cubes is one I am considering, but, as I say, its only in the past few months that the intake issue has come to light. Prior to that Ive just been getting my ideas from books such as the vizard ones, but now I realise that most example set ups include less restrictive intales that wont fit. I wasnt sure if this would also be a restriction if I go with more cubes or not?

I have a manual tranny. Im not sure on the ratio's off the top of my head (I have a cheat sheet that I have mislaid - but I recall that the ratios were pretty much stock for the model).

 

I cant believe all the time I have put into looking, and then as sson as I ask about it I find out loads more.

I have just noticed another intake that apparently fits which is the weiand street warrior.

Again, information is contradictory. It is claimed it was designed with the likes of stroker motors in mind, yet I have found comments that suggest anything other than a mild 350 would be choked wy this manifild, and that its design is very similar to the base "perfomer" !

 

If you had a 327/350BHP Id suspect it has a lowish ratio rear which helps. If you are into Vizard books get the one on intakes and carbs, he has the weiand street ram in there.

 

Use the LT-1 drop base which is the lowest I've found. You won't be able to run a choke as mentioned above but you may be able to squeeze a 3" filter under there. Good luck with your build!

 

Can anyone suggest if, for example, I was to even attempt an RPM (I know this may not fit, and I am not saying I am going this route) but just hypothetically... are there some suggested carbs that are lower than others, and will not need any "grinding" (for example without a choke, as simmo suggests).

I ask as I am going to take some measurements in the car today and I want to look up some specs on carbs and try to measure what may or may not fit.

 

This subject has been many times in the past. Somebody actually posted photos of various intakes with measurements showing how high the carb mounting surface is from the base of the manifold - I forget what they call that part of the block. In any event, I have a GM, Winters cast, LT1 high-rise manifold on my 350, under my stock '69 hood. I use the stock drop base air cleaner that came with the car. Here is a photo of the intake on the car:

And just so there is no confusion about the air filter on the car, here is a photo:

Based on information I have the Edlebrock RPM intake is sort of a clone of the LT1 intake and is similar in height. I have ~½" clearance between the hood and the the air filter top, and have no indication that there has ever been any contact between the two.

Cheers,
Pete

 

Pete, you are right, this has been covered even more than I had thought initially, but I do feel I have asked some additional questions regarding the carb that did not seem to be covered in most of the posts I have read.

In addition, whilst you may have posted your pics and info previously, I havent yet come across it.. so many thanks for that.

I hadnt heard of the Winters intake, but looking into it a little I found a thread elsewhere that talks of a guy who compared specs to a stealth intake and found it was lower at 4.75 - 5.25, but when he purchased one (p/n 3933163 ) found it was 4.75 - 5.75)

Either way, unless your intake is another variant again, it seems taller than an RPM at 4.20 - 5.25).

Interesting

 

Sorry CairnsFella, I wasn't criticizing you for asking the question, just commenting that this subject, like brake problems, keeps popping up.

Winters Foundry cast all the aluminum intakes, and probably other parts, for GM back in the day. If the part has a snowflake cast on it, it's from Winters.

I'm pretty sure if you go with the Performer RPM and the drop base air cleaner assembly you won't have any clearance problems. That was the point I was trying to make.

Cheers,
Pete

 

Ok Pete... thanks for the clarification.

 

I installed the edlebrock performer ESP and 600cmf carb this winter used a 3/4 inch drop base breather # edl 1221 3x14 and have 7/8 inch hood clearence http://i920.photobucket.com/albums/a...00306-1408.jpg http://i920.photobucket.com/albums/a...00306-1415.jpg

 

Thanks for this.

Do you mind me asking if you know what your stock clearance was. I appear to have about 1" as is (and I now realise that there is already a drop base on there.. I assume they come as standard?

 

While that intake is indeed cast at the Winters foundry for GM Performance and is close to the shape of an LT-1 intake it is NOT! an LT-1 intake.

You may want to consider a Brodix HVH-1016 intake if your Vette has a manual transmission, I have a good used one for $140USD. They will make as much HP as an Edelbrock RPM air-gap but, give plenty of clearance to a small block hood. My Email is zeohsix@gmail.com if you need photos.

Here is a link to the intake I'm talking about: http://www.brodix.com/manifolds/sbmanifolds.html

 

Cheers Solid.

Ill have a read up on that intake and get back to you.

Thanks again

 

Solid,

I have had a brief read up on that brodix intake. At this point I would have to say that the quoted range (3000-6500) is a little higher than I would prefer.

Still.. I wont count it out.. this is merely an investigative phase anyway.

Thanks again.

 

Sorry to chime in late ... I have a Torker 2 with 650 DP Holley under a 69 SB hood which fits well. It certainly seemed drivable on a zoomy 355 before I took it apart 7or8 years ago, despite a quoted range of 2500 - 6500 (from memory). It is an old design and a bit of a compromise single plane manifold, but works for me.
Dave

 

I have an edelbrock performer intake manifold on my '74 l-82 and that fits under the stock hood with a holley carb and a normal air cleaner. That should work for your 327 convertible i think

Will