Ok Im landing a real nice 330 Firedome soon and have been doin some research on the net re Desoto hemi combos. Im aware of what is and isnt available parts wise, but what I'd really love to know is who here on the HAMB has built a nice strong, firebreathing Desoto hemi tall deck? Im looking to swap out the stock rods for Pontiac H Beams, Ross forged pistons, port the heads add decent valves, and have Chris Nieslon or Crower grind me a nice blower cam from the original core. Nothing radical just the right combo of parts, CR etc to get me 500+ GENUINE HP with a GMC 6-71. Anyone been down this path, what did they learn and what would they have changed? Thanx in advance....... Rat
Venolia did my pistons (354) at a fair price, great quality and faster than would do 'em. George at Clay Smith ground my cam. He recommended a little different grind for my blower application than the other guys usually stock. 500 HP from a streetable DeSoto may be a bit of a stretch...
check out scootermcrad. He has a Hemi tech blog and keeps track of tons of other Hemi related topics. I have a Semi-Hemi, so I'm not much help. Good Luck!
r.b. my 341 has been warmed over, but not to the extent that you are talking about. mine is 60 over with a chris nielson reground cam. the intake is a stock adventurer 2x4 with two 500s. the ignition is stock later model chrysler electronic. big block chevy waterpump. homemade lakes headers and a 700r4 round out the package. hope this helps. dan
Thanx for the info. Ive seen Scoots blog.... Mr Ford thats one nice Fireflite !! Thats an Eelco 6x2 and a Joe hunt elec conv mag "look" dissy yah? Keep the info comin guys, im lookin to make some decent HP/TQ from a blown 330. Rat
I put a 330 Desoto in my 41 Chevy. Used Chevy intake valves because they were 8 dollars each compared to 25 dollars each for Desoto valves. Had Camcraft here in Md. regrind my cam. Bought standard bore pistons for a 292 Ford Y block to use because they are .030 larger than my stock 330 bore. Pin placement was right on also. These were much more affordable than buying custom made Desoto pistons. Fabricated a 6-71 blower intake out of aluminum that also has a water crossover. I'll post pics later as I'm having trouble uploading them tonight. The engine has been in the car about 10 years so far with many trouble free miles. I run 2 AFB's with about a 10 percent underdrive.
Hey 41 Hemi...now youre talkin. id LOVE to see those pix. Krooser why does 500HP sound like a "stretch" to you? Factory dual quad Desotos made 320-345HP with an avg little cam and mild CR and breathing thru crappy manifolds. So what youre saying is that with ported heads, better machining, a nice juice cam, decent valves, spark and a 6-71 with decent headers we can't make another 150HP or so? Have you built one like this? Pls elaborate? Thanx Rat
Here is your blower manifold- http://www.jalopyjournal.com/forum/showthread.php?t=218550&highlight=desoto+hemi&showall=1 I have headers for the DeSoto's and intakes.. @ www.lakeheaders.com
Maybe I'm just being a little conservative, I dunno. I figure my 354 with the 671 will do about 500 hp. I've got a Clay Smith cam, it's .090 over with 8-1 slugs, 555 heads and stuff. I like to run real mild cams so you get good mileage... and I've never ever cared how much HP I had... it has what it has and who cares what the # is. I just think with a street cam you'd be hard pressed to get 500 hp...
OT-oldkid (Dan)Your car was the inspiration for the car I'm building right now. I think it's one of the nicest sedans I've ever seen. Great job! Brian
Although '41' apparently has been successful with the ford slug, if you really want to make 500 hp then spend a few extra bucks and use a forged piston and Total Seal ring set. As with any blown engine, hp has a direct relationship to the amount of boost you use. The amount of boost also has a direct relationship to the quality of the parts used and a couple hundred small details to keep it alive. Skimp as much as you want but don't blame the engine if the numbers aren't there. The last blown 392 we built for a customer was North of $18K when it went out the door.... .
Hi guys---to answer you HotrodA we did have to mill little reliefs in the Ford pistons. Also the pin holes in the pistons needed to be slightly honed to get the correct measurement. The only difference in dimensions in the Chevy and Desoto intake valves was the stem diameter and the valve retainer. I was installing new bronze guides anyway so I just got ones that fit the smaller diameter Chevy stem. With the smaller stem this actually ended up a performance plus as less space is taken up by the smaller stems in the ports. The intake valve size for Desoto 330's is 1.94. My engine was built with street dependability in mind; not really for performance if you will. I feel that the "frugal" purchases never sacrificed quality for my street engine. I think that figuring out what fits this and what is the best combination for that is just plain old hot roddin' !! Al
Hey guys great info keep it coming. 41 hemi what size intake and exh valves did you use? They were 11/32" stems right ? Krooser, I hear what ya saying re HP etc.... How do you define a "street" can? Duration @ .050" less than 230? I consider a cam with 235 deg @ .050" in a 340ci engine a "cice" street cam....with cams in the 245-250 @ .050" starting to "get there" in terms of streetablity. But the reality is that I dont really care about daily driving streetability in a weekend ride - I wan to make decent HP/TQ so that if i need to run a stick with more than 235 deg than thats what I will do to get there. The other point is that even a cam thats has 245/250 deg of duration will be somewhat TAMED by that 6-71 lung sitting on top of the engine...thats the effect that Roots blowers have on lumpier cams. Trust me when i tell you that this engine WILL be more than streetable when Im done with it. 73RR...that 18K 392 ever go to the track or see the engine dyno? What were its numbers if I can ask? I wont be skimping on the quality of this mill as that is not the way I build my engines. I believe 12-15 lbs of boost with the right fuel, porting, custom Ross forged pistons, H beam rods, prepped factory steel crank, mains studs and a main cap girdle or steel caps will do the job easily both in HP production and longevity/reliability. Heads will be O ringed for decent seal and I will run head studs. An MSD 6BTM will dump timing a selected amount as boost rises for detonation prevention. Have done a fair amount of research and believe BB Pontiac H beam rods can be substituted. They are the almost the same length centre to centre, and need about about .020" off each side of the rod for rod side clearnace although Im looking to confirm the exact measurements atm. I must admit I didnt know about the 292 Y block slugs compatibility in OD and pin height hehe !! Thoughts? Rat
Can't remember actual measurements(been 10 or so years) but the Desoto stems have a larger diameter than the Chevy. Used the Chevy 1.94 stainless intake valves common to the 327-350 engines. Could not find any other make exhaust valves that could be substituted for the Desoto exhaust valves so I just got the stock Desoto replacements from Kanter I think. Good luck with your build Al
That engine was shipped to England, destined for a 35 Ford coupe at last report. The engine was on the dyno in England but numbers not made available to me. I will assume that they were up to expectations or I probably would have received a phone call..... A very similar package about 10 years ago made 1050HP and 1100lb-ft torque at 12 lbs boost. The availability of so many good con rods makes swapping a breeze, we only have to look through the numerical listings and find something close to what we need and then decide the best 'fix'. If the Poncho listing is only 0.020" fat you might consider stretching the journal so that the Pont bearing can be used. Save some $$$$ on inserts. This is our standard process with 440 rods on the 392 crank. ...And if you are serious about 15lbs of boost you may also want to consider removing the rolled fillet on the journal. Weld it up and put in a proper radius. My $0.03 (inflation ya know...) .
I have a FAIR 330 in my sports coupe. You can see a short vid slip of it on SCOOTERS blog spot. Its O.K. .... But my Old 291 woulda Spanked its ASS. But my Rig Aint well Loved around here cus it has no paint & No Small Block Chevy !
i build fabricated blower intakes for tall and short deck desoto hemis or any engine for that [email protected]
I'm not an expert. I don't own a shop. I'm not trying to start an arguement here. I've read many times in several different books, on line, and Chrysler information, etc,... that,.. most manufacturers simply grind a radius at the rod & main journals to help prevent cracks. Chrysler used the more expensive & effective rolled fillets. The process of making a rolled fillet compresses the grain of metal at that point and increases the strength to help prevent cracks. What is best? What are the advantages of doing away with the rolled fillet? Lucky667
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