How Do Engine Components Like Airflow and Cams Determine Horsepower?

[Mgt3]

I have five grand in cash to start, but it's not like that's all I'm willing to spend. The motor doesn't have to be completed this month. I'm 21 right now, and as corny as it may sound I want to build an engine that I can keep for the rest of my life. I've talked to a number of MOPAR guys who tell me that Chrysler blocks are the strongest ever built. I'm intent on assembling a V8.

 

[Mgt3]

Does anyone make hemispherical heads for the SBC?

 

[Ranger Mike]

Dr dodge..jump in here
in my opinion the Chrysler big block can be that engine...I used a 400 CID b block and stuffed a 440 cid stroked crank shaft into it and estimate it made over 600 HP and awesome stump pulling torque..idled like a gummers grocery getter and was bulletproof...parts are readily available and last forever..now here is the good news for you...you can do this gradually over a period of years...the 400 CID V8 with stock components is a very good base line..add aftermarket things slowly..like good ignition, good intake and exhaust manifold, then do a flow bench port job on the heads..save your money for the stroker crank and new pistons, the stock Y con rods will live for a long time..just remember when you go to the large CID you need a new cam shaft...
these engines are relatively low rpm engines 7000 rpm is usual limit and breather great...hemis are the top of the line but they cost!

dollar for dollar in the overall total performance world the small block Chevy is probably cheaper but there're some unique design features of the B block Mopar and in my opinion..there is no substitute for cubic inches...and this is one moderately cheap way to get to a 500 CID engine that will LIVE..
and there is a set of aluminum hemi heads tha tmay be added to thsi B Block...Indy Cylinder heads makes them i think

the SBC " hemi" heads are probably cost prohibative and the al. heads already developed for the SBC are great performers..but the mega cube solution tops out at 405 CID on the standard SBC without huge dollar mods to make it live.

 

[dr dodge]

I am a big block mopar fan, for sure. I have built lots over the years, tough as a hogs nose. We have a 400 stock bore in a 74 charger (very heavy car) that runs strong, and when I was driving it to work, got 25+ mpg (unless you stomped on it alot) my current engine going into my 72 challenger is .040 over 440, KB 10:1 pistons, and brand new aluminum heads from 440 source (less that $1000 fully assembled) steel crank, h beam rods. unsure of the cam as yet. goal a solid 400-500 hp, gobbs of torque, pump gas, everyday driver, and 20 mpg on the hiway.
SBC parts are cheaper, but a stock 360 w/ a $400 rering has way more bottom end, will easily outrun the stock chevy unless you drop in a bunch of parts so it will handle rpms, then the costs get out of hand fast (lots of $$$ on the valve train, and they are chronic cam lobe "rounders" with the heavy springs.
$5k will build a very good mopar engine, and tranny, with possibly some change to put into suspension, too (I will have less than that in my challenger engine and tranny, but do everything myself)
and many of my big blocks have run way over 100k miles with no engine failures, and I am NOT easy on them

dr

mopar or no car

dr

dr

 

[Mgt3]

Dr. Dodge, what is a 'cam rounder'?

 

[Ranger Mike]

From Mopar Engines from Chrysler Corporation
old stuff since this s the 9th edition but still relative

 

[Ranger Mike]

forgive me doctor dodge for jumping in
SBC are HIGH revving engines..8000 RPM is typical but
becuase of the reciprocating weight of the valve, rocker arm, push rod , lifter , the valve spring pressure must be increased. the weakest link of this SBC is the valve train. excessive pressure springs may cause material to be worn away on the cam shaft lobe face...if oil supply is interrupted at any time, additional wear takes place. SBC typically ar high revving engines that put a lot of stress on the components because of the hi RPMs...one solution to the above reciprocating weight was to go to over head cam that eliminated a bunch of weight like push rods, the lifter became the lifter/adjuster and the cam acted directly on the rocker..no more long camshaft timing chain to stretch and vary timing at hi revs.

 

[Mgt3]

So that's why people say OHC engines are better suited to high RPMs.

What is the longevity of a big block hemi? I think this is the engine I'm going with.

Just out of curiosity, why do Chevy engines suffer from camshaft wearing, but the MOPARS can live at high RPMs? Stronger parts?

Thanks for all of the help, you guys are great!

 

[dr dodge]

Just out of curiosity, why do Chevy engines suffer from camshaft wearing, but the MOPARS can live at high RPMs? Stronger parts?

I have my opinions, but I think it is a function of how straight the pushrod/lifter angle is and induced harmonics
because chevy's use studs in the head, there is a lot more wobble, as opposed to the mopars which use a rocker shaft that stops all the twisting. The SBC needs big springs, pinned/screw in studs, poly locks, guide plates, and stud girdles. A SB mopar will sing to you all day long at 5 grand with all stock components. (the worlds greatest street stock motors... everyone thinks you are cheating, hand you $150 to tear down, and walk away scratching and shaking their heads)

sorry if I offended any chevy guys

dr

 

[Ranger Mike]

Hemis live forever..the early hemis 392 CID introduced in 1957 are still in use today in drag racing..albeit re-sleeved and only the block and heads are original..
the 426 CID series introduce in 1965 are still excellent but expensive..one bit of trivia..these were introduced in 1964 and the fuel dragster guys were really disappointed in the performance..real dogs when set up to FACTORY recommended specs..I think it was Don Garlits or Pete Robinson who got totally torque off at the performance and said.." the He-- with it, I'm going to blow the sucker up." anyway one of them cranked in about 50 degrees lead and ran it ..he E.T. better than he ever had..the hemis came on all the way to 9000 RPM once you dialed in the ignition timing way advanced and 50 degree advance is a LOT...hemis are high RPM motors..

one reason SBC wipe out cam lobes ( specifically the older version SCB) is due to the fact that the rear most main bearing is lubed by NON filtered oil...only 80 percent of the mains are oiled by oil having passed through the oil filter...also the front cam lobes are lubed from the main bearing galleries and if you do not restrict the oil galleries properly , oil will not lube the lobe as required at high RPM.
All the Mopar oils all mains with filtered oil. One more thing..all the mopars use a rocker shaft that the rocker arm and the rocker are moves up and down as the camshaft dictates. This provides for a more stable control of valve geometry and there may be a very small reduction of actual reciprocating weight with this design. I suspect the cam lobes are wiped due to improper oil gallery preparation. SBC can live but you need some external plumbing and you need to do your homework.

 

[dr dodge]

ranger mike,
I never thought about the dirty oiling, but that makes sense as most wipe out the rear cylinders. I don't remember ever seeing a front one rounded off. most old chevy engines that have rough idle and/or intermittent miss will have a low lobe

good thing they're cheap

dr

 

[Mgt3]

That's all I need to know. I'm passing on a Fleetwood for sale down the road with the LT! and building a Hemi!

I don't know the dimensions, but I'm fairly sure that the Hemi in one of those 32 Ford styled fiberglass bodies would be an incredible vehicle.

 

[Ranger Mike]

32 five window coupe with a Hemi...i have seen them...awesome
welcome to the big dog club...let me know how it goes..will help where i can
Ranger Mike