Im in the process of building a 355 with a Holley Stealth Ram induction system and I was wondering if anyone knows of astrut tower brace that will clear the upper plenum and hood. I currently have a 305 tbi so its kinda hard to judge it without actually swapping the intakes and having the STB to measure, especially since this is a daily driven car. I askd some of the guys at Jegs and they had no idea. Im planning on running an L88 style fiberglass hood so i may get more clearance from that but im not sure yet. Any help would be appreciated.

 

I know with the factory hood the Stealth ram is pretty much touching it, or at least what I can remember?

Would be tough to find one to clear

 

none exist for the stealth ram... the HSR is roughly 2 inches taller than the stock plenum and puts the TB at a completely diff angle thats why the HSR TB will run on the underside of the hood. any strut tower braces that have been made for TPI cars will NOT fit the HSR....

u'll just have to fab up ur own... its not difficult, just measure and cut some tubing. im gona be doin the same thing when i instal my hsr 383. the hood is a good idea for the HSR since u will need the room over the stocker. but the strut brace should be made to fit the hood as well. dont even bother modifying an aftermarket brace either. good luck

 

You can use a BMR one with 2" aluminum blocks under each end. Works good.

 

Did this clear with the stock hood? We are in the process of making one now for the TPI, we were going to do the Stealth Ram next if it works. I haven't installed the Stealth Ram yet to know..

Thanks!
Ryan

 

let us know how the stealth ram one works.... my throttle body on my HSR hit the bottom of my stock IROCZ hood. i had to cut abit out from under the hood.

I have no idea how you would run a strut tower brace in there without a big cowl hood

 

Stock hood. BMR fits over the TPI and it will fjust fit the SR Plenum.

 

post some pics.
I have the RA1 hood and a Jamex bar and I put some wood under the mounts to see if that would work and the ends would hit the hood.

 

the biggest question here is how toasted are your motor mounts? are the original or new? Old mounts can lower the engine almost a half inch and at that point you may have clearance for the STB, but anything higher there may still be issues

my 2cents

 

Sorry about the quality. Click on it and you should get a bigger pic so you can see.

 

That cleared with a stock hood with out cutting it?

Thanks

 

I havent been able to get on here much, but thanks for all the replies. Im going to be using a tubular K member so ill probably end up using new motor mounts too so unless the k member geometry is a little lower it will be at stock ride height.

 

anyone out there using a stb with a hsr with stock hood...

quality pictures would be appreciated.

 

im not sure how close it would be but u could get the BMR one to work( its gona be really close). the HSR(well the TB/intake duct) hits the bottom of the camaro hood and the firebird. often ppl have to remove the hood brace to get the clearance needed. the BMR one is a good bit thinner(where it goes over the plenum) than the UMI one. and since it also sits farther back toward the rear of the plenum it wouldnt be in the highest point of the HSR (TB area). i would think GCpoland's would clear barely. but it would be super tight. unless u had a aftermarket cowl hood. i think he said its touching. and replacing your stock motor mounts will increase engine height about 1/2" especially with the poly engine mounts.

if the STB is resting on the plenum this wouldnt be a good idea. since when u give the engine gas the engine twists in the engine mounts. esp with stock rubber mounts the engine twists a good bit. this will cause interference with the plenum and STB. can cause damage/noise etc. poly engine mounts altho they raise the engine height they also greatly reduce engine twist. this would allow for a closer fit of the STB to the plenum if poly engine mounts are used.

 

I've been wanting to put a STB on my car with HSR for years. I decided to get one and start playing with it.

Right now it still hits my factory 91 Z hood, and the current location only leaves a couple MM clearance with the motor, but I'm going to keep trimming the hood supports a little bit at a time and possibly grinding down the ribs on the intake, only where needed, to see if I can get it to work... My spacers are around 7/8" thick on each side currently.

EDIT: I should add, this is with fresh rubber engine mounts. I just swapped the engine last winter.



Clearance between STB and HSR plennum

The two lower black marked bracing are what seem to be makimg contact, I plan to trim those down a little at a time, and only where necessary.

You can see the scratches from hood contact with my first test hood slam closed.

 

Does BMR advertise this piece to work with the HSR? Just curious. I guess not surprising that it would end up in contact with the hood with that amount of spacers under the strut tower mounting points. A little angle mill / planing on those fins ought to help, then you could pull spacers, and maybe not have to cut the hood?

 

No, I called BMR and they specifically said it didn't, but it is still the slimmest offering where it goes over the plenum...

I think I may need to do all the above, and keep the spacers... I'm not sure how much the engine twists with rubber mounts, but I'm sure it's enough for it to touch the brace until I knock down the ribs on the intake...

 

Yeah, I would think that the engine torqueing over on rubber mounts(even poly mounts perhaps) could cause some touching. I would take the plenum to a machine shop and have them mill the top fins off and mirror polish it. I'd be very surprised if the cooling fins really allow for a temperature drop on the plenum.

 

interested in this but for the Edelbrock pro flo - which I suspect leaves even less room.

Curious, and hopefully comes across as a constructive query - would the spacers impact the ability of the STB function? i.e. permit more flex between the strut towers?

 

I have had hard time thinking any intakes are taller than the stealth ram that fit under the factory hood. I had to move the Worm screw from my tb hose clamp to the bottom because it was wearing a hole in one of my hood supports.

I specifically made my spacers out of solid steel, I dont think I'm giving up much of any strength. May not be the case for other spacer methods...

I frimmed as much of the hood support as I was willing to last night. Still light contact, but if the stb and hood are both stationary, maybe it's OK? I'll have to see if it rattles or anything...

 

If you cut the center rib out and make the hole slightly larger on each side then make a sheet metal box for that area and weld it in, then you would have the clearance that you need and maintain the integrity of the hood. I don’t think you would have to mill the fins on the intake if you did that.

 

In the areas where I cut out the bent portion, it is really only one thickness of the sheetmetal still protruding beyond the underside of the shape where the blisters go, maybe less. I don't see anything more being removed from the hood without cutting all the way through, which I would prefer to avoid...

I'm leaning more towards chamfering or blending the stb. I can always reinforce it if I need to also... It's on a relatively steep angle which makes me think I would only have to be modifying the rear half if anything... I'll have to take a pic of the remaining contact tonight.

Clearly, it's really tight and I understand why not many, if any, people have pulled it off with the factory hood...

 

You trimmed that away very neatly. Someone who didn't know better would think it was made that way.

 

You can see these few little marks made in the wet paint. Only very minor contact... I may leave it and see what it does, or break the key edges on the center plate of the STB to reduce contact...


3 or 4 minor spots of c9ntact in the wet paint.

Another view of the STB / HSR clearance. Its tight! For reference the plate on the STB is 5/16", so clearance is maybe about 1/8" currently without modifying anything under there yet...

 

I got out the cutting tools... and my 3d printer!

I ended up trimming down the Finns on the front of the intake plenum, then blended and smoothed them. I tried to match the approximate angle of the plate in the middle of the BMR STB, which alredy matches the angle of the hood in that location.



I also took the STB to my belt sander and took material off the front bottom edge to increase clearance with the intake and throttle body, this allowed me to test a couple different thickness test spacers I 3d printed to find the minimum I could get away with.



I ended up taking a bit more off the front edge of the plenum after taking this pic. Maybe a bit more off the STB as well if I remember right...



I'll test fit it all again tonight and post a pic.

 

Interesting development, if anyone tries doing anything like this in the future. The center of the STB moves substantially when tightening the inside bolts, at least on my car. I had been test fitting with the outside bolts only, well snugged down, but when I installed the inside bolts, the center of the STB is now touching the intake. so I need to take a step backwards...

I got two of my spacers surface ground at work taking off about 0.050" so I'll try test fitting that combination soon, and report back. If needed I'll probably keep stepping it down 0.050" at a time till I find a spacing that fits... Hopefully one exists...

 

I would not have expected that much bending.

 

So I wanted to mathematically try to determine how much clearance I really need between my intake and the brace. I test fit everything last night with my current surface ground spacers are resulting in about 0.175 at the closest point, BUT it is still making some contact with the hood also...

I mocked up the general shapes on cad, determining the radius about the crank shaft is about 20", if the motor actually rotates more about the motor mounts, those are higher so it would reduce the radius and the clearance needed, so I'm using the crank as a worst case scenario. The intake width is about 6". I found online people claim most sbc's twist about 1-2 deg under heavy load. I also showed a measurement for 3 deg as well. So, this results in a total vertical movement of between 0.094" and 0.131" for 2 deg and 3 deg rotation accordingly. The intake is also not a perfect rectangle, the current contact is in about an inch or so from the outside edge, so that reduces the relative vertical movement too.

I think I'll try taking about another 0.040" off my spacers and try again next week.

I did have another thought I need to test though. To even be able to get into the wheel well to tighten the STB bolts I have to lift up the front end a little bit to fit my arms in there, my car is lowered. I have the front end of the car jacked up about an inch from the center of the K Member, wheels are still touching the ground. I wonder if I let the car back down if things will flex differently and give me a different amount of clearance??? When we are talking such small amounts of clearance, all these variables may matter...

 

Ha, the clearance did change when I let it down off the jack... Now measures 0.204" clearance, was 0.175" before while lifted from the k member.

 

After taking another .050" off my spacers, I'm down to a .138" gap when the car is off the jack on its wheels. Still touching the hood though, before the hood latch makes contact. Just over a half inch gap at the front edge of the hood.

I'll try taking another .010 off monday... That seems like as far as I'm going to be able to go, without taking nore off the intake or the bottom side of the brace...

 

I took the next .010 off leaving my total spacer stackup at right about .800. This results in a .121 gap between the intake and STB, and I don't think I want to go any farther. But, the hood is still touching about a half inch before the hood latch contacts the mechanism... I wonder if a little bit of hood contact / flex is the end of the world? I may have to take a bit of material off the top back edge of the STB... I'm running out of options...

If you're not really committed to doing this, I think the answer is that it just doesn't fit with the factory hood...