Camming a 10.3 to 1 350

[cjperformance]

No engine figure sorry , i specced and supplied all parts for this and assembled the short only, but 363rwhp @ just over 6100 with a th350 & 2600tci convertor, 3.9 gears, the car was later converted to 5spd m/t.
Those exact heads! I did not have them flowed, i do not have a flow bench, i have 2 places i send stuff to if i want a number but was not concerned for this build.
After swapping to M/T , 2 different 750's a dp and a vac were tried, both "on the street" just gave up low/mid to the eddy 650 and had no feelable improvement in top end hp, so the eddy was refitted, it was not dynoed with the m/t or the 750 carbs and yes it would make a few more numbers up top to 'impress the boys' on the printout but on the street absolutely no advantage to the bigger carb.
It did apparently "feel" nicer again at lower rpm with a 1" 4 hole spacer under the 650 but lack of bonnet height meant that at higher rpm the lower air filter required sent it rich after 5400 so the spacer came off and the bigger filter back on.

[Geoff2]

Craig,
Was that the AVS model? The new annular booster version? Carter/Edel AFB & AVS carbs are very underrated.

[cjperformance]

Craig,
Was that the AVS model? The new annular booster version? Carter/Edel AFB & AVS carbs are very underrated.

Geoff, Thunder series avs 650, great carbs.
Ive only used 1 avs2 so far but i really liked it.
I like the eddys, carter afb's, T,quads,, all a bit misunderstood and yes underrated certainly.

For a real streeter these types of carbs are hard to beat and once set up the driveabity is just so good.
Another little bonus is that you can fit an eddy carb and the tinkerers wont touch/mess with them as they look too complex, fit a holley and the tinkerers just cant help but to rejet, drill shit, cut/stretch PV springs (yes ive had a couple do that!), mess up float height etc!

Dont get me wrong i like holley & variants just as much but these days my personal view is to use them for the more serious stuff for ease/speed of tuning and "get bits anywhere" parts availability, etc.

[Scotthatch]

No engine figure sorry , i specced and supplied all parts for this and assembled the short only, but 363rwhp @ just over 6100 with a th350 & 2600tci convertor, 3.9 gears, the car was later converted to 5spd m/t.
Those exact heads! I did not have them flowed, i do not have a flow bench, i have 2 places i send stuff to if i want a number but was not concerned for this build.
After swapping to M/T , 2 different 750's a dp and a vac were tried, both "on the street" just gave up low/mid to the eddy 650 and had no feelable improvement in top end hp, so the eddy was refitted, it was not dynoed with the m/t or the 750 carbs and yes it would make a few more numbers up top to 'impress the boys' on the printout but on the street absolutely no advantage to the bigger carb.
It did apparently "feel" nicer again at lower rpm with a 1" 4 hole spacer under the 650 but lack of bonnet height meant that at higher rpm the lower air filter required sent it rich after 5400 so the spacer came off and the bigger filter back on.

If you look back I posted that it would be 461.5 HP

If you look at 363 rwhp and do a common 20% loss on the driveline you get 454 engine HP and I would bet the car was at lest driving the waterpump alternator so you are right at the HP the math said ..

So the question is rpm ... the 2 things that effect rpm are intake runner length and cid ....I used 11 inch runner length and a 350 cid ... more on either and calculated rpm goes down ...

After crunching some numbers this wouldn't happen to be a 400 cid motor ?

Carb size is a hard thing and has been made harder by carb company's playing with how they are rated ... all the math I used is based on dry flow on a flowbench with a given pressure drop ... my rule of thumb is used cfm times 3.44 .... so in this case 244 cfm x .92 z = 224.5 x3.44 = 772 cfm carburetor to support the flow ....this number is Max needed at Max rpm ... for driving around a little lower cfm will drive better..

[cjperformance]

350ci , rpm airgap intake.yes running stock type waterpump, alternator, elec fuel pump & fans.
By prior experience i dont think the cam spec V the rest of the spec is off for rpm peaking just over 6100, as i said it would show more with more carb at a little more rpm but id no way expect that to be anything over 6300.
Id never think or be telling a customer that an engine like that was going to peak at 6900 id be out of business.
I know holley test at 1.5" for the 4 barrel range , to be honest i dont 'know' what edelbrock carbs are tested at but im sure its 1.5" aswell?

[Geoff2]

Craig,
Preaching to the converted here. Been using TQs since the late 70s. I have two of the very rare Competition Series TQs, 850s. I used to buy old AFBs for $10 a piece, could take my pick from 44 gal drums full of them. Because of the junk metal that Holley used, I have found two good uses for for them: stops the lid of the garbage bin blowing off & they make excellent door stops.....

[Warp Speed]

Craig,
Preaching to the converted here. Been using TQs since the late 70s. I have two of the very rare Competition Series TQs, 850s. I used to buy old AFBs for $10 a piece, could take my pick from 44 gal drums full of them. Because of the junk metal that Holley used, I have found two good uses for for them: stops the lid of the garbage bin blowing off & they make excellent door stops.....

You left out Holley type carbs Winning more races than all others combined.........by about 100x!

[Frankshaft]

OP, what if I told you, I could help you pick a cam, giving you a choice of 4 or 5, that would easily achieve your goals, that would cost you $69.95-$99.95 tops, and I wouldn't charge you a penny? No simulators, no cfd, no 1D program, no formulas. What would you say? Or anyone on here for that matter. Its just really not that complicated.

[groberts101]

OP, what if I told you, I could help you pick a cam, giving you a choice of 4 or 5, that would easily achieve your goals, that would cost you $69.95-$99.95 tops, and I wouldn't charge you a penny? No simulators, no cfd, no 1D program, no formulas. What would you say? Or anyone on here for that matter. Its just really not that complicated.

This is absolutely not a knock at your experience so please don't take it that way.

I'm guessing there are many people here or elsewhere.. who could "nail it" pretty closely in 4-5 choices, but I think what he's after here is maximizing towards the absolute best bang for the buck in his 1st "best new cam" choice/install. Welcome to the club and is exactly why custom cam grinders exist in the wild.

So, it usually boils down to a "by who's standard?" thing and just because someone's on a budget.. doesn't necessarily mean they want the engine to run like every one else's budget engine.

Personally speaking.. I want a budget engine that runs like a super-stock engine.. so I keep fiddling and trying to learn new tricks.

[user-30257]

OP, what if I told you, I could help you pick a cam, giving you a choice of 4 or 5, that would easily achieve your goals, that would cost you $69.95-$99.95 tops, and I wouldn't charge you a penny? No simulators, no cfd, no 1D program, no formulas. What would you say? Or anyone on here for that matter. Its just really not that complicated.

This is absolutely not a knock at your experience so please don't take it that way.

I'm guessing there are many people here or elsewhere.. who could "nail it" pretty closely in 4-5 choices, but I think what he's after here is maximizing towards the absolute best bang for the buck in his 1st "best new cam" choice/install. Welcome to the club and is exactly why custom cam grinders exist in the wild.

So, it usually boils down to a "by who's standard?" thing and just because someone's on a budget.. doesn't necessarily mean they want the engine to run like every one else's budget engine.

Personally speaking.. I want a budget engine that runs like a super-stock engine.. so I keep fiddling and trying to learn new tricks.

Pretty much any cam in the 22X 23X duration will do what is wanted. No need to spend 150 dollars to have someone spec you a cam that can be bought for less than the spec price alone.

[RevTheory]

220, 230... whatever it takes

I think the OP did a hit and run anyways.

[user-30257]

No engine figure sorry , i specced and supplied all parts for this and assembled the short only, but 363rwhp @ just over 6100 with a th350 & 2600tci convertor, 3.9 gears, the car was later converted to 5spd m/t.
Those exact heads! I did not have them flowed, i do not have a flow bench, i have 2 places i send stuff to if i want a number but was not concerned for this build.
After swapping to M/T , 2 different 750's a dp and a vac were tried, both "on the street" just gave up low/mid to the eddy 650 and had no feelable improvement in top end hp, so the eddy was refitted, it was not dynoed with the m/t or the 750 carbs and yes it would make a few more numbers up top to 'impress the boys' on the printout but on the street absolutely no advantage to the bigger carb.
It did apparently "feel" nicer again at lower rpm with a 1" 4 hole spacer under the 650 but lack of bonnet height meant that at higher rpm the lower air filter required sent it rich after 5400 so the spacer came off and the bigger filter back on.

If you look back I posted that it would be 461.5 HP

If you look at 363 rwhp and do a common 20% loss on the driveline you get 454 engine HP and I would bet the car was at lest driving the waterpump alternator so you are right at the HP the math said ..

So the question is rpm ... the 2 things that effect rpm are intake runner length and cid ....I used 11 inch runner length and a 350 cid ... more on either and calculated rpm goes down ...

After crunching some numbers this wouldn't happen to be a 400 cid motor ?

Carb size is a hard thing and has been made harder by carb company's playing with how they are rated ... all the math I used is based on dry flow on a flowbench with a given pressure drop ... my rule of thumb is used cfm times 3.44 .... so in this case 244 cfm x .92 z = 224.5 x3.44 = 772 cfm carburetor to support the flow ....this number is Max needed at Max rpm ... for driving around a little lower cfm will drive better..

Why will less gym drive better. My little work truck with 100 less cubes has 1000cfm throttle body stock. I'm sure those engineers were idiots.should have used 350cfm for it to drive better

[randy331]

Pretty much any cam in the 22X 23X duration will do what is wanted. No need to spend 150 dollars to have someone spec you a cam that can be bought for less than the spec price alone.

I agree. I don't understand all the fuss over a few deg. duration or 1-2 deg LSA thinking they are giving up power when it's a street cruiser and they are giving up piles of power with lift and valve acceleartion.

Randy

[CGT]

Pretty much any cam in the 22X 23X duration will do what is wanted. No need to spend 150 dollars to have someone spec you a cam that can be bought for less than the spec price alone.

I agree. I don't understand all the fuss over a few deg. duration or 1-2 deg LSA thinking they are giving up power when it's a street cruiser and they are giving up piles of power with lift and valve acceleartion.

Randy

I also agree. How many people claiming 1 and 2 degree camshaft miracles do you think completely mapped either of the cams in question? Very very few. Camshafts will always be mysterious voo doo though in my opinion. People prefer it that way, cam companies prefer it that way also.

[groberts101]

It's all just useless fuss caused by too big a toes getting stepped on.

How many here have built this EXACT same engine, every single spec' right down to the tailpipes included? So without all the necessary A,B,C,D,E,F,G testing.. it's all just speculation and conjecture anyways.

I personally like a rattier sounding engine with as much usable mid-range torque at ALL throttle angles, as I can possibly muster out of it. Don't give a damn if its narrow and I need to kill 10 ft/lbs immediately off idle and snuffs out 10 more right at peak to make the sweet spot even fatter either. Others like a tamer easier to tune combo with a bigger topend pull. Acceptable powerbands and driving style is very subjective to say the least and to each their own and everything in between.

At least I try to explain my standards and choices made to get there, rather than pushing my own on others by dismissing the "need for this or the need for that". Only the OP can decide what he prefers to have for the final product.