My old 72 455 was rebuilt last year and FINALLY went on the dyno this morning! TH-400 is currently being rebuilt and will all go into the 71 Riv by the end of the year. More to come... eventually... I'm the big dummy who thought I could get 500hp out of her with little funds. Pipe dream! But, she did pull 372 horse and 462lbs of sweet, dirty torque. I am saving up for the TA aluminum heads but will likely stick with the stock exhaust manifolds. If anyone has any input, questions, or heavy criticism, I will gladly accept.
Forged pistons from TA .030 Erson E630021 cam Edelbrock Performer intake and 750cfm carb New TA HEI distributor I think just about everything else is stock.
Theres likely more in there. It will like more carb. Port the ex manifolds or add headers and curve the dist or even possibly go MSD with a 6AL2 box.
Erson 630021 Adv Duration, 292/310 .050 Duration, 214/226 Gross Lift, .478/.493 Lobe Center 114 Power Range, 1500-5000 372 HP, 462 TQ, I'd say those numbers are pretty good.
Yes, 500 HP with stock exhaust takes lots of testing and lots of money. I can attest to that. 372 with your mild build is quite good. Your Riv will love you. Have fun.
That’s what I would expect from a of that small intake duration cam in a 455 and well less the .525” lift which is where real good things start to happen even with stock heads. don’t knock yourself, pat yourself on the back!
Replacing that carb is definitely the first step. That being said more air in always needs more air out. Heads are going to be a big power maker but I fear that then you'll find the rest of your combo is the limiting factor and won't be using them to their full potential, thus meaning more money needed to upgrade the rest, otherwise its kind of a waste. My recommendation based on your setup is to get a slightly bigger carb and some shorty headers, then get it back on the dyno and tune it.
i don't think I ever told anyone that there cam is to small but your cam is too small and the LSA is to wide and the ramp is to slow.it is so small is actually hurting your torque. with the right cam you should get 390-400 hp and 475-485 tq. don't waste your money on headers with that small of a cam not much to gain. best bang for the buck change the cam.
I'd imagine that cam is smooth as silk and if you want that in your Riv, that's a good torque cam. It should haul that boat around really nice and 372 is nothing to sneeze at.
To all of you folks telling him to get a bigger carb have any of you looked at the fuel usage numbers on his dyno sheet? they are great, in fact it could be argued that in some places a slight richening up would make for fatter TQ and Hp numbers.
Just to clarify for everyone, I am NOT looking for 500hp out of her. I read a Car Craft article years ago in high school about a 500hp 455 and it gave me pipe dreams with which my wallet disagreed. I'm 100% convinced that I'll be happy with this combo for now. Maybe a few bolt-ons in the future, but a fun left lane cruiser is my main goal. Not looking to win any races, just lookin for a good time. Story of my life, really. Lol
Power looks good. IIRC the 500 they got was with aluminum heads and a bigger cam. As-is the cam you have is just a lot like a Stage 1 cam with some extra lift and intake duration so not a bad cam for a heavy car and probably no gears. The easiest thing you can do is try a 1" 4 hole spacer, maybe an open spacer? The carb cfm isn't the problem. The way those carbs open up the secondaries is the problem. Standard 455 came with 750 cfm but the secondaries can open up much faster when set up right. The Edelbrock carbs have sluggish opening secondaries so you probably won't get more top end power but the mid-range will certainly pull stronger. I see the dyno looks like it has crush bent pipes attached to the exhaust manifold. That cost a few HP so get good 2.5" TA downpipes and mandrel bent exhaust at least to good mufflers. 2.5" crush bent over the axles won't affect you as much. A mild converter upgrade to 2000-2500 stall will make a huge change in the way the car feels compared to the heavy low stall 13" behind the T400 with no downside. Nothing fancy name brand converter will do from Jegs/Summit. Assuming they are stock exhaust manifolds something you can do for a few bucks is find a machine shop that can use a 2.25" or 2.375" hole saw to open up the exhaust outlets. That is the big bottleneck on the manifolds. No porting necessary unless you go to the aluminum heads. As far as other stuff that could have been done, did you have the block/heads surfaced at all? You want to make sure you are actually at 9.5:1 at least, maybe a little higher. Also on stock standard valve heads having the valves back cut and a nice 3 angle valve job. Stepping up to Stage 1 valves would have been good too. Always things you can do down the road.
Check the plugs see if a little lean. Jet the carb according what you see. Strong cruiser motor Shawn! Good work here.
