KJL

I am concerned over how well it will perform on the street. I still feel like there was a reason for the jump. I think the dyno is as accurate as any. He builds lots of racing engines for guys that know a lot more about this stuff than I do. If it turns out to be a dog on the street and after I get my fill of bragging how much HP it has, then I will just cam it down, probably keep the heads though.

MotorHead

Yada yada yada, give me a break, going to subscribe to this thread so when he takes it out for a spin it is a blast to drive in any gear at any speed just like mine I will dig it up.

My dyno curve looks about the same and the Vette is a blast to drive on the street from idle to 7 grand. It also runs mid grade gas, doesn't even need premium.

The guy makes almost 700HP and the small parts engine and otherwise guys gotta get there poking sticks out. We will see how it is on the street and you guys can concentrate on the motorhome engines.

scott foxwell

I don't think it does make almost 700hp. Not with that dyno sheet, and even if it does, it only makes "almost" 700hp for a few worthless rpm (no offense KJL). At 6000 it's not even making 600hp but ya know, I beleive that YOU believe that somehow it magically jumps to "almost" 700 hp in 250 rpm and then just sits there. Do tell.
And this isn't about poking sticks, it's about an honest assessment. I don't mind if you disagree, but disagree with some facts and not your typical school boy playground loudmouth bully tactics. Talk about poking sticks. 'Course, if that's all you got...

63mako

Peak dyno numbers are what sell engines. Torque in the RPM range you use it the most is best suited for the street. There are a lot of 400 HP engines that will smoke a 450 HP engine in every category except peak HP reading on the dyno. Guys buy that high hp crate engine, drop it in their automatic car with 3.08 gears and wonder why their old engine seemed almost as fast, had better throttle response and way better to drive. Too many people don't get it. As far as the OP is concerned his trans and rear gearing will help streetability big time. Pretty mean build.

uxojerry

Im not sure why there is so much negativity related to this engine. The dyno graph may not have been in the best format but it didn't look all that drastic. Considering shaffiroff sells the same crate motor (700hp), would lead me to believe the numbers are correct. Maybe there is a better cam out there for this engine. Peak power came on at 6150rpm and held until the end of the pull. There was plenty of tq at the beginning of the pull.

I also wouldn't think the heads are too big. Every performance forum around will mention afr 245s for an sbc 434. There are plenty of results on other forums backing kjl's dyno numbers. Maybe Im biased as I have a pair of 245s in my garage for a future build, lol.

I personally would be very discouraged if I spent $13k on an engine, shared the results, and had people pi$$ on the build.

KJL

Hahaha, I am fine with the opinions. I encourage them. Just to make it clear however, nobody sold me this engine based on power numbers. Tony Mamo provided the advice and component selection for induction components including heads, intake, cam, lifters and rockers and my builder handled the the bottom end stuff but also wanted to use the 4150 carb. Tony wanted to use a Dominator. I didn't want to jeopardize assistance in the future with tuning so I decided to stay with the 4150. I wanted to push the envelope with this build. My goal was to maximize the capability of the 434 but still have good streetable power. I wanted this combination to be on the radical side as this car is not a daily driver. I do encourage anyone who is following and commenting on this thread to also offer data if possible. I am trying to get the April copy of CHP for information on their 434 build as well.

As far as the dyno accuracy is concerned, impossible to know for sure. All I know is this family has been involved in drag racing sense the 60's and building race engines for 30 years. There is no reason to question the numbers at this point unless someone can provide data for a similar build, which I would love to see. I have seen many claims regarding performance numbers over the years on the forum but few dyno sheets. I am hoping my build along with Paul's and others will provide some solid information regarding these large displacement small blocks.

427Hotrod

If you get it to the track...the MPH will tell what it's really making.

Either way...it's going to be fun!

JIM

StraubTech

Observation 1. The use of a Marine carb. Why? HP style 4150's are used all the time. HP style carbs have one the Carb Shoot Out each year when held at Bo Laws done in FL. Carb modifiers made HP carbs by had for years. The J tubes are a safety feature, not a performance issue. If my money I would have to question this.

Observation 2. I have been around Dyno's since 1989. EXCEPT in a situation you are testing NOS I have NEVER seen an NA SBC engine gain 50HP in 200. Power will not just jump like that.

Observation 3. The dead flat power from 6200 to 6900 is the sign of either an unhappy valvetrain or a huge restriction. I would bet if headers were changed and carb was changed to an 4150HP 1000 that there is MORE POWER in her as that dyno sheet and dead flat power for 700 rpm is screaming that.

If I paid out good money I would want to know the what's and why's on this build.

ajrothm

I think the peak numbers are excellent...the graph is a little soft in the middle but...I doubt you'll ever notice it. Gear the car to make use of that upper rpm range and it should haul ***..

Like Jim said, track mph will tell you the true story if you don't live up in high altitude etc etc.

245 heads are definitely NOT too big for this size engine spinning to 7k... Hell I would have had them ported more even..

The cam selection I question a little, no doubt that's where some of the low end power is missing but... It's capable of high rpms, that's where the power is at, so use it there.

I think it makes killer power honestly for only 434".

My buddy has a killer 11-1 comp 420" with a LOT of work through out, heads that are in the mid 250cc range (home ported) that flowed 330 ish at .600 and a custom 248ish HYD roller, Jessel shaft mounts, Super Victor with lots of port/plenum work and 3" worth of spacers and a 1000 King demon and it made 640hp and we were quite happy with that..... No doubt he would have loved another 55hp like yours.....

His car is setup very well and runs 9.70@137 on pump gas.

StraubTech

There are some red flags here. KJL has expressed he is not an engine guy but it is his money. He should get what is money will pay for. There is more in the engine. If bringing this to his attention is Pi$$ing on the build then I apologize. I look at it a informing him there are some things here that are not right.

MotorHead

I think that anyone that thinks 695HP is not almost 700HP is not even worth a response and by me saying my dyno graph is almost the same is backing it up with what I built in my basement so I know a lot more than most about this engine. Like I said you continue to build your motorhome engines and leave KJL alone, he needs no second guessing he built the engine more than correctly.

Like I said he has a phenomenal engine and doing it with 23 deg. heads and should be applauded for what he has done

MotorHead

I have 3.08 rear end and my Vette got faster and faster with each engine I put between the fenders. I know, I did it, can you say the same or are you just reading books and flinging old wives tales around again.

KJL

I appreciate everyone's input. I am humbled by the level of varied experience this forum (all of you) have to offer. While I don't build engines, I have been a practicing engineered for 30 years in various industries including trucking and automotive and done quite a few chassis dyno runs over the years and agree the dyno numbers look odd. Maybe I can track down a Dominator or a 1000 cfm 4150 to slap on there any try for ***** and giggles. I think Tony may have a Dominator he will send me to try.

StraubTech

Please post your "almost the same" dyno sheet that shows an 800 rpm constant drop in torque then a 200 rpm spike at 6000 rpm where it gains35/40ft/# in 200 rpm to ralley another torque peak.

scott foxwell

I never said 695 isn't almost 700hp...I said I don't think it's making that much power based on that dyno sheet. I realize that went over your head...sorry.
I can tell what you "know" about engines every time you post.

Now lets see that dyno sheet.

scott foxwell

In my experience, and this is what I do for a living, based on valve size and cross sectional area those heads are bigger than necessary for this combination. Unfortunately big numbers are powerful sales tools. Spinning 7000 and making peak power at 7000 are two different things.

scott foxwell

Just think of how much faster your car would be if you would actually build an engine that had good usable average power and not just big peak numbers.

63mako

A lot of people buy a crate engine pushing big peak numbers and are unhappy with the results because the rear gear and trans do not compliment the powerband of the engine. This is the point my post was trying to make. I didn't insult you or the OP

I said " As far as the OP is concerned his trans and rear gearing will help streetability big time. Pretty mean build."

I don't believe this was insulting in any way???

Why then would you choose to attack and insult me personally?

I have been doing this for over 40 years. I was hand porting heads and machining components for some of the top NHRA guys in the country before I was 20. Built or helped build hundreds of engines, mostly small blocks. There are dozens of guys right here on the forum that I corresponded with throughout their builds via emails and PM's and lead them through the entire process start to finish. Many have tiny cams and tiny heads in your opinion but the build specs fit their displacement, requirements, intended use, gearing, trans, driving style and budget and never had anyone contact me after the fact disappointed in their results. My 383 only pulled 527 hp. Never used the 150 nitrous shot on the dyno. So obviously, I have no clue on any of this. I apparently have no idea what I am talking about.

KJL

These are the numbers from Shafiroff's 434 build. Nice numbers. Not much in the way of specs other than AFR 245 heads. The curve shape looks uniform. I am sure they also spent a bit more time tuning it for than we did. Hydraulic roller lifters as well.

KJL

My data: