[joina]

hi all first timer here, im rebuilding my 350 chev and am really stumped with how much HP and tourqe it will produce. im not building a racer not by a long shot just wanted something with a good smooth idol but still a bit of get up and go if needed. engine is going in a boat and has a new set of hi flow exhaust manifolds on it. here are as much engine specs as i know.

cylinder bore diameter 4.060
engine stroke 3.480
compression ratio 9.45:1
engine capacity 5906.71cc or 360CI
416 camel hump heads, new valves and springs
edelbrock eps intake manifold
standard on crank
600 holley carb
cam 260 advertised duration, 212@ .05 cam lift, .420 valve lift
new oil pump
new fuel pump
engine has also been balanced.

now i know its not going to be big power but thats not really what i was after but its just that the cam shop and engine machine shop reckon it will get up to between 295-310hp but then a good friend of mine thinks it will only make about 250-260hp and im wondering who is closer.
so if anyone out ther could help me out with this it would e very much appreciated, thanks in advance!!!

[2wld4u]

decent CR and yea it should make 290+ hp but you need good exhaust headers/etc... Id go with a lil more cam with .480 lift and around 220 duration @ .050 tho

[Blazin72]

Don't 416 heads have 58cc chambers? Were your pistons selected accordingly? If not then you could have a bit more than the 9.5:1 compression.

I'm going to estimate 275hp.

[joina]

Thanks for yourthat reply, Yeah exhaust should flow quite nicely. Cant change cam now as i have already purchased and fitted the one i have mentioned.

[joina]

Originally Posted by Blazin72

Don't 416 heads have 58cc chambers? Were your pistons selected accordingly? If not then you could have a bit more than the 9.5:1 compression.

I'm going to estimate 275hp.

the heads were tested and came in at 62cc, i got new dished piston to bring the compression down to 9.45:1

[vinniekq2]

For comparison only,,,
The 350 that came in my 1981 vette was rebuilt when I bought the car.
The cam was a 420 lift cam similar to what you described,holley street dominator manifold, 650 cfm double pumper I had built with 850 base plate. 9.5-:1 compression, small tube headers. After chasis dyno tuning the peak power was 205 horse power peak at 4500 rpm and max torque was 279.These figures were determined by a "dynoJet" dyno.This in rwhp.

The car barely got out of its own way,lol.Seriously that might work out to 275 ish flywheel H.P.
BTW,the base H.P. was 190 rwhp before modifying the carb.

[joina]

Originally Posted by vinniekq2

For comparison only,,,
The 350 that came in my 1981 vette was rebuilt when I bought the car.
The cam was a 420 lift cam similar to what you described,holley street dominator manifold, 650 cfm double pumper I had built with 850 base plate. 9.5-:1 compression, small tube headers. After chasis dyno tuning the peak power was 205 horse power peak at 4500 rpm and max torque was 279.These figures were determined by a "dynoJet" dyno.This in rwhp.

The car barely got out of its own way,lol.Seriously that might work out to 275 ish flywheel H.P.
BTW,the base H.P. was 190 rwhp before modifying the carb.

sounds like you and blazin72 are talking roughly the same hp numbers i was kinda hoping for a little more but i cant expect to much out of such a mild cam, what heads were on your 81 vette?

[vinniekq2]

the stock 194s with a 3 angle grind.Most GM heads from that era did not have big flow numbers.

[327NUT]

You see it on every forum, "I've got about 450 hp" most of these don't have a clue because they are comparing their build to what I call "Magazine Motors", they over estimates their car's horse power and then when and if they ever dyno the thing reality sets in and they are very disappointed.

[joina]

Originally Posted by 327NUT

You see it on every forum, "I've got about 450 hp" most of these don't have a clue because they are comparing their build to what I call "Magazine Motors", they over estimates their car's horse power and then when and if they ever dyno the thing reality sets in and they are very disappointed.

Yeah mate that's why im asking as i said im not expecting big hp just a good guess from people who may know. No way im comparing it to any of tour so called magazine motors!

[joina]

Originally Posted by 327NUT

You see it on every forum, "I've got about 450 hp" most of these don't have a clue because they are comparing their build to what I call "Magazine Motors", they over estimates their car's horse power and then when and if they ever dyno the thing reality sets in and they are very disappointed.

one more thing, im from a small town in NZ without any dyno machine handy so as i said at start of my question im lookiing for a good estimate from people who are in the know, im not looking for pushed up wana be wish i had this much hp! all i want is a good honest estimate. im not expecting much just the truth!!!!!

[vinniekq2]

remember a number doesnt have any value.Horse power is just half of the equation.Torque is what you feel.Any engine that has improved breathing will be more fun than stock,especially if it is well tuned in a car that has good suspension and tires.Spirited driving is exactly that! How much spirit do you have and want?The new high performance engines also consider MPG or more important sfc.
SFC = specific fuel consumption.This is how much horse power your engine produces per pound of fuel burnt.

Curious,are you using a chevy engine or holden?

[va4cqd]

416 heads arent camel humps. they're 80s 305 heads. 461s are camel humps

[joina]

They are 461s just got my numbers round wrong way at start sorry

[joina]

Originally Posted by vinniekq2

remember a number doesnt have any value.Horse power is just half of the equation.Torque is what you feel.Any engine that has improved breathing will be more fun than stock,especially if it is well tuned in a car that has good suspension and tires.Spirited driving is exactly that! How much spirit do you have and want?The new high performance engines also consider MPG or more important sfc.
SFC = specific fuel consumption.This is how much horse power your engine produces per pound of fuel burnt.

Curious,are you using a chevy engine or holden?

Its a chev engine.