How thick is an adapter plate? I'm thinking less than an inch. Anyone know for sure?

 

it comes in many forms/makes and sizes..For an LG4 I would suggest either a 1/2" or 1" thick 4 hole spacer made of aluminum..Check your hood clearance


Daz

 

Yeah, the issue of hood clearance is why I'm asking.

 

I believe the adapter plates are very thin, prolly 1/4" or so.

Now, spacers are different. I had a 1" spacer and 4" air filter on my stock LG4 intake, but had to ditch the spacer and get a 3" filter when I got my new intake.

 

Just to let you know. A performer RPM will NOT fit under your hood If you are planning on using an adaptor plate. Adaptor plates are never 1/4". The one I had was about 1". The performer RPM barely fits as it is. You have to use a drop-out air cleaner... this is mandatory. Also the 82-84 Z28 hood has less clearance than most because of the "fake scoops".

Your options are the following:

1. Get a carb that will bolt to the intake (Holley) and get a drop out cleaner

2. Cut a hole in your hood (Cowl)

 

Hi Johny. OK, I don't have a stock hood. I have an IROC hood. Long story. I don't know if there's anymore clearance under it than there would be under the stock Z28 hood. I do have a drop-base air cleaner. It drops quite a bit, so it should help.

 

Even with the drop out and that hood, I'm pretty sure that it still won't fit if you are planning to use an adapter plate. The smallest plates you can get are around .75" thick. Since you are getting a new carb... I would suggest that you get a square bore holley. That will solve all your problems.

 

Yeah, I may have to go that route. I was just trying to determine if it were at all possible to just have my Q-jet rebuilt and use an adapter plate, thus, saving me about $400. So far, it doesn't look promising. Curses!

 

I hate to say it, but a Performer intake would suit your needs better. It is setup to take either squarebore and spreadbore carbs, without a spacer plate. When I researched for my setup I was met with alot of obstacles. Hood clearance is a major issue unless you plan on going with a cowl induction hood. If you go with a Holley carb, do not get a dual feed, a drop base won't work with it. Holleys are also taller than your stock q-jet. Edelbrock is about the same as the q-jet. To check for hood clearance take some modeling clay and make 5 cones 2-3 inches high. Place the cones on your existing air cleaner one at each side and one on the center nut. Close the hood and open it and check the cones with a ruler. this will tell you how much room you have to play with.

 

Hi Kev. I did a variation on that test already. That's why I was asking about the thickness of the adapter plate. As for the perfomer RPM, I have already bought it and I got a seriously good deal on it which is largely why I bought it. I get the impression that most people think this was a bad idea. I want to make it work though. The darn thing looks so innocent sitting on our diningroom table, next to the drop base air cleaner and other goodies.

 

Ill trade you a Performer 2101 for it

Daz

 

I know exactly how you feel. You should contact 88farmkid. He is a member here that attended our first Dyno Day. He was running with a Performer RPM and a Holley carb. He might be able to give you some insight as to what was needed to get it to fit. He had a 350 that kicked out 275+ RWHP.

 

Thanks Kev..I'm looking him up now.

How's the Mrs feeling anyway? Better I hope.

 

I agree with Johnny's numbers on plate thickness- minimum 3/4". The point is that the plate bolts to intake using one set of mount holes- and the fastener head (usually an allen-head type bolt)has to be contained within the spacer (i.e. flush with the top mounting surface) so that carb will mount flat. Then- there has to be enough material in the spacer to hold the carb hold-down bolts so carb doesn't rip out the first time you push on it sideways (i.e. more than 3/8"). Now- add in the thickness of a carb gasket (or two- depending on how well adapter plate seals to intake on its own) ...

 

Edelbrock Part #2732
1/16" Adapter Plate

 

That unit is for using a square bore carb on a spread bore intake.

The one she needs is for a spread bore carb on a square bore intake. Minnimum .75"

 

My bad... Hey Johnny IROC... I have the Edelbrock Performer intake, non EGR... Than I have the Performer 1406 carb... My intake is spreadbore right? My carb is squarebore... Why dont I need that 2732 adapter? My carb bolted straight to the intake... Should I have this adapter? If not, whut size spacer would u recommend... Its a 350 bored .30 over, I know it has roller rockers, performer intake, performer 600 cfm carb, hedman headers, etc... Ive been havin some carb problems and no one can seem to set it properly... Just wondering if this adapter or spacer could be the problem?

 

performer intakes have both the spreadbore (q-jet) and squarebore (holley, edelbrock). 600 cfm will work for the 350, although i am sure it could handle at least a 650 cfm no problem. exactly what kidns of problems are you having? i am sure a good tuning will solve most of the problems.

 

When I hammer it off the line, it kinda sounds like it winds up before it moves..... I hit the pedal, seems like it sucks air, than takes off.... Theres some kind of delay.. Northern Performance tuned the carb n did my timing n said it was dead on.... But I dunno... Once I get moving it flies...

 

Vacuum leak?

 

If your square Bore Carb has vacume secondaries you could possibly be experiencing the dreaded Quadrabog on Your non Quadrajet Carb.

Secondaries are opening too soon.

Ric

 

Hey Johny we just helped 383 Smoka High Jack this thread

Narly Dude:hail:

As for Your Dilema Copper Chick I am sure somebody could make you up an adaptor plate using flat Head Capscrews to attach plate to intake. Going this route I think the plate could be made as thin as 3/8".

I think somebody??? on this board with a Black TransAm has the skills and tools to do the job. I bet you could sweet talk him.

Ric

 

I think yer right ratchet.... U can hear it bog.. Like i deep low sound... Can I just put in step up springs n that'll fix it?

 

I missed the original question..IMO an adapter plate is bad for performance as your introducing something that hinders flow(by changing the flows direction)..I would do it right and get the proper carb for it

Daz