airboat camshaft help

[F1Fever]

Around here you can pick up a 5.3 with harness and brain for 450-650 bucks very often. For the cost of heads and cam plus gaskets oil etc that would be another viable option.

[F-BIRD'88]

The 217 heads just need porting.
Don't be shy with the die grinder.
They flow well and make very good power
Once fully ported.
That and the crane cam I listed will make
Very good power @ 5500 rpm. Right where
You need it. Then tune prop pitch to dial in new
Boat speed. More horsepower @ 5500 rpm allows more boat speed.
(Because it now allows more prop pitch).
This is how you do it.

Get serious with the die grinder. They'll work good.
Finished port volume will be a good 10cc bigger.
170++CC. Just right. A felpro 1205 gasket is a good guide.

[induction apprentice]

He is on a budget. How would he afford the poor fuel consumption from the poor BSFC of a blown application?

From what I see he is on the right track using his bumps and a good cam choice.

[F1Fever]

Budget is spend $500 at the local wrecking yard on an efi 5.3 and sell the 350 for $500
Upgrade to 6 bolt mains, roller cam, modern design aluminum heads and efi.

[induction apprentice]

Interesting diversification in opinions.

[racer10j]

He is on a budget. How would he afford the poor fuel consumption from the poor BSFC of a blown application?

From what I see he is on the right track using his bumps and a good cam choice.

This is exactly what i'm going to do and i'll let you all no how it turns out. But....

Budget is spend $500 at the local wrecking yard on an efi 5.3 and sell the 350 for $500
Upgrade to 6 bolt mains, roller cam, modern design aluminum heads and efi.

I will certainly check into this option as well. I never dreamed that i would be able to buy the later model stuff that cheap. I will be calling the wrecking yards in my area to check prices. This is very appealing to me if in fact i can do it that cheap.

[Rizzle]

Budget is spend $500 at the local wrecking yard on an efi 5.3 and sell the 350 for $500
Upgrade to 6 bolt mains, roller cam, modern design aluminum heads and efi.

I will certainly check into this option as well. I never dreamed that i would be able to buy the later model stuff that cheap. I will be calling the wrecking yards in my area to check prices. This is very appealing to me if in fact i can do it that cheap.

If EFI isn't your thing, the individual coil conversion box retails for a couple hundred, and carb intakes are also available. The MSD ign boxes are ridiculously easy to use and set the curve. Don't forget to add the price/install of an electric fuel pump/accessories/accessory drive for whatever setup you have if going the late model route.

[MadBill]

Don't know how well those things corner, but the lower center of gravity of an all aluminum engine couldn't hurt...

[racer10j]

Don't know how well those things corner, but the lower center of gravity of an all aluminum engine couldn't hurt...

I couldn't agree more,but i am fairly new to the airboat world so i don't really know how it would effect the handling. i can only imagine that it would be easier to get up on plane because of the weight loss. by the anyone know what the weight diff would be between the LS engines and the earlier small blocks?

[Rizzle]

A dressed aluminum gen III+ weighs around the 450 lb mark. An iron Gen III+ would be another 80lb or so. I'd say the weight difference between iron block/aluminum heads for both engines is probably slightly in the SBC's favor, the iron gen III block is a stout piece, but it ain't no paperweight.
The cheapest aluminum gen III's are going to be the L33 5.3 from 2005 - 07 in trucks, and the LS4 5.3 from the impala SS.
The LS4 is going to have some differences, bellhousing bolt pattern is the 60* v6 (gm small pattern) and the front cover/drive/crank is all shorter.

[racer10j]

A dressed aluminum gen III+ weighs around the 450 lb mark. An iron Gen III+ would be another 80lb or so. I'd say the weight difference between iron block/aluminum heads for both engines is probably slightly in the SBC's favor, the iron gen III block is a stout piece, but it ain't no paperweight.
The cheapest aluminum gen III's are going to be the L33 5.3 from 2005 - 07 in trucks, and the LS4 5.3 from the impala SS.
The LS4 is going to have some differences, bellhousing bolt pattern is the 60* v6 (gm small pattern) and the front cover/drive/crank is all shorter.

Thanks for the info. a quick search last night did not seem to be very promising for the LS swap due to $$. I am going to dig deeper though and check all the wrecking yards i can find in the D/FW metroplex area and there are lots of them. Maybe i'll have some luck there. Meantime i'll be swapping on my double humps and trying out my circle track cam that i still have. If only i could remember all the specs. Hopeful that it works. Ill have to research the cam and get specs.

[Tuner]

A short-track cam should be good in that application.

Did you look at the propeller paper (in the link)? When you are at MAX RPM, is that in high (max load) pitch?

Find the story on the web about Charles Lindberg flying the P-38 in the South Pacific in WW2. He taught the other pilots about flying at WOT with the prop pitch at max load (high gear-overdrive) and the mixture control leaned to reduce the power to the desired cruise RPM. He figured it out when he was flying the US mail and used the technique to get the necessary range for his solo flight across the Atlantic to Paris. He was landing after a P-38 combat sortie with half his fuel left and everybody else near out. The mechanics asked, "Did he go all the way with you guys, he didn't burn near as much fuel." When they asked him what was up he was surprised they didn't use the same technique. He showed them his trick and the extra fuel range let them get to Admiral Yamamoto. He thought he was safe beyond the max range of the P-38, fooled him.

[induction apprentice]

Cool!

[n2omike]

Meantime i'll be swapping on my double humps and trying out my circle track cam that i still have. If only i could remember all the specs. Hopeful that it works. Ill have to research the cam and get specs.

Some good double hump heads along with a small cam should work pretty well. However, I would stay around 218-224 @ 0.050" on the intake if you're worried about fuel mileage. A 'circle track' cam might have too much duration and overlap to make a day on the water very affordable. lol

Good Luck!

[CamKing]

This is all you would need with your current heads.
Cam# H70330-71330-110
224/228 @ .050"
.495"/.495" Valve Lift
110 LSA