General Category > Quadrajet Carb Talk and Tips
adapter plate
Cliff Ruggles:
The Victor Jr is leaving a LOT of power on the table for what you are doing. Power in terms off off idle, low and mid-range.
I'd change to a stock or Performer intake with a spread bore pattern and forget about spacers and adapters.
The reason I say this is that you are running a 2000 stall speed converter and 2.73 gears. That keeps the engine WAY out of the efficient range of that intake most of it's life.
It will idle better, smooth off idle, and butt-tons more efficient in the "normal" driving range with greatly improved low and mid-range power with a low-rise factory, mid-rise factory or Performer intake on it.
I'm also curious as to the rest of the engine specs, heads used, camshaft specs, etc?.......Cliff
old cars:
454 Mark 1V, sonic tested, bored .030 with plate, 0 decked, line honed mains, lifter bores grooved.
Pistons: icon 779 with Total Seal rings, 1/16 ring package file fit. 9.5 to 1 compression.
Cylinder heads: oval port 346263 (peanut port) 2.190 intake, 1.880 exhaust, pocket porting, runners and chambers cleaned up, 3 angle valve job with blending and cc'd 118cc. Comp roller tip rockers.
Camshaft: David Vizard spec'd, 273 duration, 107 LCA at 4 degrees advance, 227@.050 / .542 lift
hydraulic custom ground on Lunati Voodoo lobes, Lunati springs
Rods: BBC oem, cleaned, magna fluxed,resized and fitted with ARP bolts
Recipcating asembly balnded
Fuel System: 780cfm Holley on Victor Jr replica by Profession Products
Cliff Ruggles:
Cam isn't big enough and LSA too tight to see all the benefits of the big intake either.
Ya, I know, Vizard knows more about this that I do and loves that tight LSA stuff and quick ramp designs. Nothing at all wrong with that deal, plenty of ways to skin the cat, but I'm NOT fond of the higher spring pressures they are recommending and using with a lot of these "modern" lobe profiles. It's hard on EVERYTHING involved, pushrods, rocker arms, lifters, cam lobes and even drags the timing set harder.
I use and prefer much longer seat timing, wider LSA, bigger lobes and less reversion, plus I use at least a full point more compression for pump gas street builds.
The smallest cam I'd ever put in a 454 CID build would have at least 280 @ .006" and 230 @ .050" and not tighter than 112LSA. Below is a dyno chart from a customer who only used me to purchase parts for his Q-jet. The build is a 455 Pontiac, professionally ported iron heads, 9.3 to 1 compression and HR cam from Comp Cams (their recommendation) on a tight LSA and advanced with the ICL at 106.
It didn't make nearly the power they were hoping for, and some audible detonation when they tried throwing some timing at it. They spun some bearings on the dyno, and of course EVERYONE right down to the guy taking out the trash was blaming the Q-jet.
I told him to replace the cam, provided the lobe numbers and positions, 110ICL and 114LSA. He calls back after the changes, says it idles much better, and cranked out a butt-load more power, plus no "reversion" right off idle and improved throttle response, etc.........Cliff
old cars:
I know lsa/lca is widely debatable. Cam durations even more so. My intensions were to build a 454 that was very street friendly and affordable to drive on todays fuel and still make good hp/torque. 10.5 to 1 compression with cast iron heads
on pump gas is neither friendly to your motor or responsible. Long duration camshafts with a heavy car and cruising gears make for a pig on fuel and no torque where you need it. High stall converters that go with these cams will further decrease fuel mileage. We are not talking dragstrip as main use.
Most people love to overshoot duration on the camshaft they choose. Peak dyno numbers are great but don't make for a great street motor unless those numbers are in the right range for the street.
I find most racers couldn't build a strong true street engine if their life depended on it. Rectangular port BBC heads , Ram AIR 1V cams , winding the engine 6500 to 7000 rpm to make hp numbers. Been there and done that.
I am more than happy with this build. Car idles great, almost smooth, drives like an electric motor, tons of torque for 2.73 gears, fuel milage is very acceptable, and it runs on 91 octane. Can you say that?
550 ft lb by 3800 rpm and 500 hp by 5000 rpm
They couldn't do this in the old days even with the higher octane gas .
Up here in Canada fuel was normally $ 1.35 a litre, thats $5.00 per american gallon for 91 octane.
My point being it is irresponsible to build a true street car without without considering these factors.
tayto:
where abouts in canada are you? im in vancouver, it was $1.35/L for 87 octane until covid....
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