90 7.4L intake manifold
#21
VIP Member
![](https://www.offshoreonly.com/forums/images/icons/prop.gif)
![Default](/forums/images/icons/icon1.gif)
An Edelbrock Performer intake and K&N filter charger yielded a 100-150rpm increase on my engine.
Then free flowing exhaust (Stainless Marine) gained another 100-150.
My old boat went from about 60mph at 4500rpm to 63 at 4800rpm with the same 23p prop...
Then free flowing exhaust (Stainless Marine) gained another 100-150.
My old boat went from about 60mph at 4500rpm to 63 at 4800rpm with the same 23p prop...
![Drink](/forums/images/smilies/drink.gif)
__________________
Patrick
Patrick
#22
Registered
Join Date: Dec 2000
Location: Beautiful Lake St. Clair,MI
Posts: 513
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
I would say just the intake manifold change alone would not be worth time time or expense. However it does look better and you shed some weight. I bet most of what Pat saw was from the switch to headers. The manifold I have is specifically made for the q-jet. Yes Weiand also makes one. Infact I used a Weiand on large oval 049 heads with the q-jet. It worked great.
#23
![Default](/forums/images/icons/icon1.gif)
I agree, intake alone will do little. Intake with cam is better, but you may have to change valve train components now and the cam must be compatable with your compression or you may loose (this reads, stay resonable on the cam unless you plan on upping compression). Intake with cam and heads even better. Intake with cam, carb, heads, and exhaust that all match is the best. But now you will be spinning more rpm and the bottom end may be risky. Minor changes end up leaving you wanting more which leads to major changes which gets costly. I do it myself all the time.
I dont think theres much wrong with the stock manifold on a stock engine except the weight.
I dont think theres much wrong with the stock manifold on a stock engine except the weight.
#25
VIP Member
![](https://www.offshoreonly.com/forums/images/icons/prop.gif)
![Default](/forums/images/icons/icon1.gif)
Originally Posted by Whiteknuckle
formula31,
I agree with everything you said. Working on these things tends to develope into a sickness!!![Big Grin](/forums/images/smilies/biggrin.gif)
I agree with everything you said. Working on these things tends to develope into a sickness!!
![Big Grin](/forums/images/smilies/biggrin.gif)
![Roll Eyes (Sarcastic)](/forums/images/smilies/rolleyes.gif)
__________________
Patrick
Patrick
#26
Registered
Thread Starter
![Default](/forums/images/icons/icon1.gif)
Could i get away with putting this manifold on and also a K & N flame arrestor? I don't want to lose performance, i just figured i might gain a little something for the summer and maybe compliment the intake and arrestor with a cam and lifters for next year. I've changed an intake before, but not a cam, so i want to read up on that. Also, if i was to buy a cam, what should i get to compliment that intake and original heads. I'm not looking for something real aggressive, i still want to be able to pull a skier out of the water but i want to play with the motor some and get some extra ponies. thanks for the info guys, it's good stuff
#27
Registered
Join Date: Dec 2000
Location: Beautiful Lake St. Clair,MI
Posts: 513
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
Sure, go for it. Don't expect a whole lot, but I can see you are determined to do this. RMBuilider on this web site is an excellent choice to work with in selecting a camshaft. He will help you out and can set you up. Good luck!!