Recommend a tunnel ram/carb BBC

[rfoll]

Can you post a picture of this beast?

[F-BIRD'88]

Car real weight (ambulance? 4500 lbs?) with driver.

If he is dead set , I recomend The Edelbrock Street Tunnel Ram Oval Port.. 2x 650 AVS2 carbs # 1905
Or 2x 750 afb #1407..
Carbs will need jetting. Ignition curve is critical.
(I suggest before making any other changes, simply lock out the diz mech advance, set for 36-38 deg fixed and try it) it will no longer be boring. nor soggy.
If the cam is a XE 284H-10 cam do this first and post result.....
Needs a bit of a converter 10" 3000+. More is better
This car is short on gearing (tires too tall).
The more car weight the more this matters
When at the track with traction it will matter.
If only running street tires and its all about burnouts it won't matter.....
The Street M/T full treaded Sportsman tires that are NOT the soft sticky Sportsman Pro tire compound will not work at all at the track. These are hard rubber compound street rod tires designed to last on the street.
The drag traction sucks. For track get ET Streets, or Sportsman Pro. Or M/T slicks The more tread you burn off these the better they get. For track get SHORTER tires than 32"...

[F-BIRD'88]

If the piston have ANY Dome then AFR head combustion chamber to piston dome clearannce MUST BE VERIFIED.
Minor clearancing may be required.
Most bbc doned pistons are not made for these good heads.
You do not want excessive cr. True 11:1 IS TOO MUCH.
ATrue 10:1 cr is very good for street BBC's and 92 octane.
7.8:1 (flat tops) is not going to work.
Ya it matters.
If the cam is the Comp XE284H-10 hyd cam #11-250-3 is is very good and goof proof as a baseline for this purpose w street tunnel ram
Where cruising, drag power MIX and hands off engine is desired.
It seems if this car was given a serious camshaft the owner would be very irrate. Sooo.... For now it is fine.
If the piston dome is just too big excessive real cr, this can be corrected.

[cv67]

I dont know what his true CR is he seems to be somewhat in the know
I have a feeling its an older grind with slow ramps...

He is open to a 300 head if its not wasted money....

So dual 800 AVS or 750? I know the latest heads have good airspeed but I certainly dont wannt havehim spending money if it seems lazy at all.
I bet a 3k converter would do the trick...havent spent much time around it but may drive it in a few days it did sound kind of tight.
He likes the cam thats in it now but will change if need be, he just doesnt like solids, still believes the wives tale about them needing adjustment all the time.

My only experience with big blocks were basic builds.....cam ported heads etc and that was a long time ago
Even a 460 I had wiht 100 shot got lazy with ported iron heads, a not so big cam and gear unless you were in it wasnt that fun to drive.
He knows the pros/cons of a tunnel ram but this thing would look just right with it. A tubbed rough st rod like this is screaming for more than a single carb ya know?

[F-BIRD'88]

"Older cam". (284-296 H) Could be a Erson TQ40H #E120621. 284-296 220-228 @.050" 110LSA 110/110 phasing. (No built in cam advance) .542"-.542"
This will have a fairly tame idle. 12- 14 deg idle timing is fine. Fine w stock converter.

The comp Xe284H-10 will have a more agressive rough idle. (Needs plenty idle base timing, not real happy with stock converter.
You can search a few U tube vids to hear the idle in a car with this cam. There are a few. It is agressive choppy at idle.
The Erson is going to sound pretty tame at idle.
Cause it is fairly tame.

A bit tame for a TR (althou it will drive and cruise nicely). A mismatch for a single plane.
Needs to be advanced for auto trans and mild gears.
Room for improvment, for a TR. If he wants the Tunbel Ram and new AFR heads to roar, then he needs to step up the game on this camshaft.
The camshaft needs to be pulled and verified.
Probabily time for a timing chain anyway.
The Comp XE284H-10 cam is not boring
This Erson TQ40H cam is....

I was refering to the 750 afb eddy carb #1407 specificly.
Both the new 650-800 AVS2 carbs look very good for this job, to me. I am leaning towards the 650 AVS2 carbs for this one. #1905

[F-BIRD'88]

If it is a older Erson H cam I have A lil tuning tweek to liven them up. 1. Check installed phasing. If not advanced. Advance to 104, 105,,106 in C /L.
Run the intake valves set with a slight bit of running lash at idle. (Rocker set up .001", .002",.,. 003" ) especially the bigger dur Hyd cams. This makes it act/run as if it was a more modern agressive ramp cam.
The valve train will be just slightly busy sounding at idle
Like a solid. Effective if the H cam is too big and or cr is too low.
I can see the owner getting bored with this cam.
Especially with a single plane...

[Little Mouse]

Well if you go back in history when holley built the 2 inch vetura dominator and nascar did not do all high speed oval tracks the carb had to do some road race courses. So they put the better atomisation annular booster in it. The new avs 2 has at least added an annular booster to the primary side so if choosing 800 to 750 without i think you see the good answer. 454 is still a big engine. By nature in any given size an oval port is known to be better design then a square port head. The real problem with bbc is the small valve to size cubic inch ratio. Dont think you can even buy an aftermarket head today with the tiny intake and exhaust valves of chevys old oval port head and thats a good thing. Heres the thing the 265 afr you could argue is easly going to outflow the old oval chevy head and if you were to decide it was not enough in airflow it could be worked over. If you buy 290 or 300 feel its to big, then where do you go for options !!. That said ive used both chevys oval and rectangle port head on the same 454 i built both times trying hydraulic, mild solid, radical solid for a street car. Claims that the bigger rectangle head would screw you up i did not find that. As always its the cam the brain of the engine the big player in hit or you missed the tarket. Not as much the lungs/ head on the engine. 1 lousy thing i tried in that same 454 was the first ever edelbrock tarantula single plane had the carb angled on it and an 850 dp i used on it. Sorry piece of shit ever since have leaned torward dual planes on any street car. Tunnel ram gets a bad rap because of real race ones with short, big cross section, add in big plenium area. One designed for street with longer runners, smaller cross section, smaller plenium. Will pass any form of dual plane 1 or 2 carbs at 3500 leave it behind like its nothing. Its the same thing trying to compare a race tunnel ram to a race single plane, runnel ram has the advantage big time. All its runners are exact same length. Then each carb is placed exactly over the runners holes. Then the dual plane manifold has a disadvatge that ine of its pleniums is smaller the other. You can crutch the smaller weak one with adding volume with a spacer but yiu cant make things equal on it.

[F-BIRD'88]

Even look at the possibility of the cam being a Crane Hyd cam 284-286 in to 294-296 ex ish durations
Should be upgraded so the TR and AFR's can be all it can be on this 454 while still being a "street motor".

[F-BIRD'88]

My preference is for the 290 cc oval port AFR head for this. Althou both the 290cc oval port and the 265cc oval port move plenty Plenty of air each.

[Little Mouse]

Air does not like to make turns. A duel plane has huge problems in that area, then it has the different size plenuims. A tunnel ram gives a nice strait line shot as possible to the vavle no twist and turn balony, then you have the carb in the right position right over top of the runners.

[Little Mouse]

Uneaqual length runers and twist and turns suck eggs, only way i can put it.

[F-BIRD'88]

If this 454 has a older style single plane eg tarantula/torker or even torker II or Weiand acelerator
Single plane manifold
And 850 and that Erson cam I can see it being Soggy, and boring, and the owner getting plenty tired and ready for a change.

[Little Mouse]

Tarrantula not spooky enough, lets do a sorpion gotta love edelbrock, im telling you avs 3 will be out in few years with full annular boosters. But shelby he would bite you with a deadly cobra and you were dead.

[Little Mouse]

To OP. If you have driven a 396/375 hp that had the 300 runner rectangle port head they ran plenty strong everywhere. I built a 2 bolt main version of one put in my 66 vette and i had a chance to drive original 396/375 hp 1970 camaro all kinds of tq. The very mild solid lifter cam made it work. The cam does engines in not the heads. This experence is why i recommended the 300 oval port afr. Could one argue the 300 head with the lower rpm hydraulic cam not be used to its potential yes you could. Would using it with that mild cam really hurt i would argue not a chance. If the 300 head did not do the 396 in it sure wont do the longer stroke bigger bore 454 in.

[Little Mouse]

To OP. If you have driven a 396/375 hp that had the 300 runner rectangle port head they ran plenty strong everywhere. I built a 2 bolt main version of one put in my 66 vette and i had a chance to drive original 396/375 hp 1970 camaro all kinds of tq. The very mild solid lifter cam made it work. The cam does engines in not the heads. This experence is why i recommended the 300 oval port afr. Could one argue the 300 head with the lower rpm hydraulic cam not be used to its potential yes you could. Would using it with that mild cam really hurt i would argue not a chance. If the 300 head did not do the 396 in it sure wont do in the longer stroke bigger bore 454 in.