i am getting ready to build my slant 6 and i need some tips
i am installing
electronic ignition
hi po coil
2bbl intake
headers
towing cam
oversized valves
and a supercharger from the superchargerstore.com

can yall give me some tips for this build

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

Welcome to the board! What's your expirence with buiding engines before? Whats the cost of the Paxton set-up from the Supercharger store these days? The search tool will be your friend! I still use it after two years.
From personal expirenece which is about two drops in the sea of information here the two barrell just didn't satisfy my need for speed. It's a cheap switch over, but with what your panning already I don't think that it's a huge worry.
Second, the reason I asked for the price of the supercharger store was that it was a couple thousand if I remember right. Well, the thing with me and boost is that if your are going to boost your engine you need to build the engine around the boosting component, the go big or go home play. So..... if the supercharging store is still charging somewhere around $5000 I would step back and plan something else. I have a feeling that a real strong N/A motor coupled with nitrous would be a much more satisfying motor, or to be patient for what the Austrailian guys are going with there m90 intake set-up.
So, the money I would spend around on stuff would be starting with the bottom end having balanced to help the engine spin. The strength is there to a degree, but the stroke is the slant's natural enemy of higher rpms. The long rod engine is a cool set-up or custom pistons, or simply doing the norm and shaving the head to increase compression. Continuing on with the bottom end you didn't metion anything about a cam. Though it is true that for low boost a stock cam will perform great, but we want excellent which there is custom grinds for boost that will help. Windage is a concern, but I tend to let people solve that themselves.
The head will need a lot of love, which is where the power is made, regardless of boost (I know that can be argued). So a simple port clean up and bigger valves; don't forget about guides. 340 valve springs can also be utilized.
Your done with the innards now so there is ignition which you've touched on and headers. I believe that the exhaust scavanging still works even if your boosting the motor. The whole idea is to exhale all the burned gas before you meet the collectors so it's all new gas entering the chamber, but that is where the cam comes in, with to weak a cam or springs boost can blow through.
So I've kinda detoured away from plan A huh? However, this is part what I have done and part what I wished I would've done. The only thing is I spent $800 and was very satisfied with my n/a build, which I could add nitrous or light boost with very quickly and have a strong motor. So the hopes would be to be able to slowly do what I metioned above for less than half the cost of the supercharger store, than plan on what power adder you would like which hopefully there will be the m90 intake availble, or perhaps your satisfied for the most part with this motor and would like to go ahead add use nitrous (it's pretty popular) which would be signifcantly less. Well, I think I said some good ideas I hope let's see what the other guys got!

well i did save money on the headers and intake i bought them used for about $350

how high could i boost the compresion and still have it streetable i mean have 2 drive the car to school and back and to the parts store

one more question could i rig up one of those thermoquad big block carbs to my sl6 or would i just flood the engine?

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

would engine build consiter rebuilding a 8 horse briggs and stration?

well i did save money on the headers and intake i bought them used for about $350

how high could i boost the compresion and still have it streetable i mean have 2 drive the car to school and back and to the parts store

one more question could i rig up one of those thermoquad big block carbs to my sl6 or would i just flood the engine?

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

Well, I have no idea about the thermoquad's rating.... sorry my mastery is very small in the department of big blocks. I would pretty much be patient and find a 390cfm carb. They are pretty common and not horribly priced new, we even used one on a 289 once.
Hey, no worries about the briggs and straton we all gotta start somewhere, mine was a 408 stroker (talk about a crash course). So.... what's going to happen though is your going to need to be willing to have your engine down for a while. Second you need to take account of the other pieces of your car that could use attention. Brakes, rear end, sway bars are all pieces that will make your car faster than an engine (I know it's counter-intutive, but very true). So maybe save some budget for those pieces as well.
So you have intake and carb done with correct? If your able I would take your engine out and strip it down somewhat. You'll have some expense of gaskets, but that will also solve some potential problems as well. The cam which can be custom ground for $100 (264 dur and .44 lift) and a head shave/clean. If you have access to a die grinder a gasket match on the intake and exhaust will really help the old girl out. Make sure it is clean clean clean when you reassembly. This coupled with the exterior parts should easily keep you under budget.
So hopefully you can scrounge for these items and keep your budget. Keep the other items in mind also!

They only come in about two flavors.... big and bigger... the small block version is in the 650-750 range... the big block version is in the 750-900 range depending on year and application (I have a couple off of 400 big blocks and there's no way I'd think about it for a slant... unless you keep the secondaries locked out).... the small block one could be worked over to fit just fine on a modded slant....

-d.Idiot

actualy i was thinking about a 500 cfm carb from demon carbs

i did mention that i was goin .30 over and using a towing cam from comp cams with oversized valves

and i have modifyed the suspention with pst polygraphite bushings, huge sway bars, and luckily my car was ordered with disk breaks,and i want to find some 340 duster torsin bars for a stiffer ride

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

To much carb is a bad thing.... if you honestly think your slant six has enough performance to warrant 500cfm than go for it. Unfortunatley I see wayyyy to many engines put on a huge carb over compensating and getting less performance than they could've with a smaller carb. I mean 390cfm on a 289 for example warranted a pretty hot rod engine with decent mileage.

Here is a fun chart to play with... it will show why 390 CFM is about right.
DD
http://www.usaimports.co.uk/Carb_Calculator.htm

but the big carb(500 cfm 2 bbl demon) is the same price as the tiny carb(350 cfm 2 bbl demon)

how do i know that it wll work with my cam to i am pu8tting a cam with 252 degrees of duration i dont want a to small carb then have a lack of air at top end

also dose anyone know if they make 2bbl carb spacers?

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

Trust the Doc, baby! He knows!

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66 Lil' Red Piggie Valiant (Mater Crusher) - Thanks Zilla!!!!! 72 Demon (Number 1 Son's)

Well, I like the plan of the same price in comparison to the carb size. Second, the 390cfm was a 4 barell carb.... does it come in the two barrel? I don't know.... but I guess I'll assume you already have the super six intake.
The calculator Doug sent ways you need about 300cfm at 5000rpm (way higher than you'll probably rev) at %75 VE. The VE is probably even gracious for a stock slant six. Now I did go back and visit your statement on the supercharger store usage. If you do plan on running the paxton set-up don't waste your time on the super six. You'll need a carb that can be addapted to blowthrough capabilities and it will be nice to go ahead and plan ahead. So... where do we stand in parts and plan now? Sounds like you picked a cam already?

I'm running the same cam with stock valves and bumped the compression to 9.2:1.... in a nut shell:

If you run this same setup, the BBD will be fine for the street, but it will go 'flat' up around 80 mph... if going NA your best bet is using that setup with a 390 cfm carb, or at most a 500 cfm carb if an edelbrock fan for use on the street... if going blown you'll need to rethink that cam profile, and find a carb that will work for your application....


-D.Idiot


"Don't fall into the 'over' trap... the common mistakes made by 'hot rod' enthusiasts...over cammed...over carbed...over geared..."

"So... where do we stand in parts and plan now? Sounds like you picked a cam already?"

ok i am going to
bore .030 over,
2bbl 350 demon carb,
super six intake(purchaced),
the comp towing cam,
clifford headers(purchaced),
electronic ignition and hot coil,
and clifford oversized valves,
then have all the machine work done

one more question what kind of machine work should i have done besides the three angle vlave job and porting

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

You need to do some measuring for volume of the bore and piston depth at TDC, and the volume of the chamber so you know how much to have milled off the block deck and head to raise your compression...

-D.Idiot